diff --git a/changelog.d/fixes/8072-catalog-provider-grouped-ordering.md b/changelog.d/fixes/8072-catalog-provider-grouped-ordering.md
new file mode 100644
index 0000000000..f1b919cd40
--- /dev/null
+++ b/changelog.d/fixes/8072-catalog-provider-grouped-ordering.md
@@ -0,0 +1 @@
+- **fix(models):** `/v1/models` now publishes one contiguous provider-grouped block per provider instead of interleaved fragments. The catalog is assembled by many independent push loops (auto-combos, named combos, static registry, codex-native, synced, OpenRouter, specialty, custom, alias-backed, connection-fallback), so one provider's models previously landed in several separated blocks. A single stable, provider-grouped sort is applied at serialization, keyed by `owned_by` (canonical owner identity) rather than the model-id prefix — so a single routable public prefix that differs from its owner (e.g. no-auth OpenCode publishing `oc/<model>` while keeping `owned_by: "opencode"`) stays contiguous. Combos are pinned first (preserving #4164); then providers in registry precedence (OAuth → NoAuth → API-key); then unknown providers in locale-independent code-unit order. The sort is stable and pure (reorders rows only, no mutation, no DB/IO), preserving combo `sort_order`, connection priority, custom append-order, and equal-id audio twins.
diff --git a/src/app/api/v1/models/catalogOrder.ts b/src/app/api/v1/models/catalogOrder.ts
new file mode 100644
index 0000000000..c0793911e8
--- /dev/null
+++ b/src/app/api/v1/models/catalogOrder.ts
@@ -0,0 +1,98 @@
+/**
+ * catalogOrder.ts — canonical provider-grouped ordering for GET /v1/models.
+ *
+ * The catalog is assembled by many independent push loops (auto-combos, named
+ * combos, static registry, codex-native, synced, OpenRouter, specialty registries,
+ * custom, alias-backed, connection-fallback). The same provider appears in several
+ * loops with other providers interleaved, so its models land in multiple separated
+ * blocks. This module applies ONE stable, provider-grouped sort at serialization.
+ *
+ * Group key = owned_by (the public owner identity), NOT the model-id prefix.
+ * Built-in providers use their canonical id as owned_by; compatible nodes use the
+ * configured node prefix. A single routable public prefix can differ from its owner:
+ * no-auth OpenCode publishes `oc/<model>` while retaining owned_by "opencode".
+ * Grouping by the prefix would split one provider's models; grouping by owned_by
+ * keeps them contiguous.
+ *
+ * Order: combo block (owned_by === "combo") pinned first, preserving #4164; then
+ * providers in registry precedence (OAUTH -> NOAUTH -> APIKEY canonical keys); then
+ * unknown providers by locale-independent code-unit order. Within a group the input
+ * order is preserved (stable), keeping combo sort_order, connection priority, custom
+ * append-order, and equal-id audio twins.
+ *
+ * Reorders rows only. Identity, alias mapping, Combo/bare compatibility (#6940/#8530),
+ * effort-variant scoping, and Claude-mirror gating are untouched. Pure; no DB/IO.
+ */
+
+import { OAUTH_PROVIDERS, NOAUTH_PROVIDERS, APIKEY_PROVIDERS } from "@/shared/constants/providers";
+
+/** Canonical provider precedence, keyed by provider id (not alias). Built once. */
+const CANONICAL_PROVIDER_ORDER: readonly string[] = [
+  ...Object.keys(OAUTH_PROVIDERS),
+  ...Object.keys(NOAUTH_PROVIDERS),
+  ...Object.keys(APIKEY_PROVIDERS),
+];
+
+/**
+ * Locale-independent code-unit comparator. UTF-16 code units put uppercase A-Z
+ * (0x41-0x5A) before lowercase a-z (0x61-0x7A); byte-deterministic, no ICU.
+ */
+function codeUnitCompare(a: string, b: string): number {
+  return a < b ? -1 : a > b ? 1 : 0;
+}
+
+/** Combo bucket key, distinct from any real provider id. */
+const COMBO_GROUP = " combo";
+
+/**
+ * Grouping key for a catalog row: "combo" for combo-owned rows, else owned_by
+ * (canonical identity). Rows with no usable owned_by fall back to the id-prefix;
+ * that path is defensive only — every published row carries owned_by.
+ */
+function modelGroupKey(model: Record<string, unknown>): string {
+  const ownedBy = typeof model.owned_by === "string" ? model.owned_by : "";
+  if (ownedBy === "combo") return COMBO_GROUP;
+  if (ownedBy) return ownedBy;
+
+  const id = typeof model.id === "string" ? model.id : "";
+  const slash = id.indexOf("/");
+  return slash > 0 ? id.slice(0, slash) : id;
+}
+
+/**
+ * Sort priority for a group key: combo first, then registry precedence, then
+ * unknown groups (rank Infinity, ordered among themselves by code unit).
+ */
+function groupSortPriority(groupKey: string): number {
+  if (groupKey === COMBO_GROUP) return -1;
+  const idx = CANONICAL_PROVIDER_ORDER.indexOf(groupKey);
+  return idx >= 0 ? idx : Infinity;
+}
+
+/**
+ * Stable provider-grouped sort. Does not mutate the input. Deterministic for a
+ * given input array.
+ */
+export function sortCatalogModelsProviderGrouped<T extends Record<string, unknown>>(
+  models: T[]
+): T[] {
+  if (!Array.isArray(models) || models.length < 2) return models;
+
+  const annotated = models.map((model, index) => {
+    const groupKey = modelGroupKey(model);
+    return { model, groupKey, priority: groupSortPriority(groupKey), index };
+  });
+
+  annotated.sort((a, b) => {
+    if (a.priority !== b.priority) return a.priority - b.priority;
+    // Unknown groups (both Infinity): code-unit order by key.
+    if (a.priority === Infinity && b.priority === Infinity) {
+      const cmp = codeUnitCompare(a.groupKey, b.groupKey);
+      if (cmp !== 0) return cmp;
+    }
+    // Stable: preserve input order within a group.
+    return a.index - b.index;
+  });
+
+  return annotated.map((entry) => entry.model);
+}
diff --git a/src/app/api/v1/models/catalogResponse.ts b/src/app/api/v1/models/catalogResponse.ts
index 597d329370..35b92c5097 100644
--- a/src/app/api/v1/models/catalogResponse.ts
+++ b/src/app/api/v1/models/catalogResponse.ts
@@ -23,6 +23,7 @@ import { buildFunctionalGatewayPredicate } from "./functionalGatewayPredicate";
 import { getPassthroughProviders, REGISTRY } from "@omniroute/open-sse/config/providerRegistry";
 import { hasEligibleConnectionForModel } from "@/domain/connectionModelRules";
 import { dedupeExactCatalogIds } from "./catalogDedupe";
+import { sortCatalogModelsProviderGrouped } from "./catalogOrder";
 import {
   disambiguateCatalogModelNames,
   enrichCatalogModelEntry,
@@ -171,6 +172,12 @@ export function finalizeCatalogResponse(
       return maybeOmitCatalogModelName(listedModel, includeModelNames);
     })
   );
+  // Canonical provider-grouped publication: one contiguous block per provider,
+  // combos pinned first. Stable — preserves combo sort_order, connection priority,
+  // and equal-id audio twins. Grouped by owned_by (canonical identity), not the
+  // routing alias prefix. Applied after enrichment/disambiguation so the final
+  // serialized order is what every consumer sees; cached as part of the body.
+  const orderedModels = sortCatalogModelsProviderGrouped(enrichedModels);
   // Codex CLI compatibility: its model-catalog refresh (codex_models_manager) does
   // GET /v1/models?client_version=<v> and decodes a JSON object with a TOP-LEVEL
   // `models` array, so the OpenAI-standard `{object,data}` shape makes it fail with
@@ -187,7 +194,7 @@ export function finalizeCatalogResponse(
   // keeps codex on its built-in model info — same inference as today, minus the error.
   const responseBody: Record<string, unknown> = {
     object: "list",
-    data: enrichedModels,
+    data: orderedModels,
   };
   if (isCodexModelCatalogClient(request)) {
     responseBody.models = [];
diff --git a/tests/unit/catalog-order-contract.test.ts b/tests/unit/catalog-order-contract.test.ts
new file mode 100644
index 0000000000..3c25d645cd
--- /dev/null
+++ b/tests/unit/catalog-order-contract.test.ts
@@ -0,0 +1,149 @@
+/**
+ * tests/unit/catalog-order-contract.test.ts
+ *
+ * Provider-grouped ordering contract for the unified model catalog.
+ *
+ * Red-first: proves the current tree publishes fragmented provider blocks.
+ * Uses the same DB module set and reset pattern as models-catalog-route.test.ts.
+ * /api/models, quota-short-circuit, and inbound-alias cases are split into
+ * separate files to avoid extra module imports that break the sql.js lifecycle.
+ */
+
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-catalog-order-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+process.env.API_KEY_SECRET = process.env.API_KEY_SECRET || "catalog-order-secret";
+
+const core = await import("../../src/lib/db/core.ts");
+const providersDb = await import("../../src/lib/db/providers.ts");
+const modelsDb = await import("../../src/lib/db/models.ts");
+const combosDb = await import("../../src/lib/db/combos.ts");
+const apiKeysDb = await import("../../src/lib/db/apiKeys.ts");
+const v1ModelsCatalog = await import("../../src/app/api/v1/models/catalog.ts");
+
+async function resetStorage() {
+  core.resetDbInstance();
+  apiKeysDb.resetApiKeyState();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+  fs.mkdirSync(TEST_DATA_DIR, { recursive: true });
+  v1ModelsCatalog.__resetCatalogBuilderRunsForTest();
+}
+
+test.beforeEach(async () => {
+  await resetStorage();
+});
+
+test.after(async () => {
+  core.resetDbInstance();
+  apiKeysDb.resetApiKeyState();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+async function seedConnection(provider: string, overrides: Record<string, unknown> = {}) {
+  return providersDb.createProviderConnection({
+    provider,
+    authType: (overrides.authType as string) || "apikey",
+    name: `${provider}-test-${Math.random().toString(16).slice(2, 8)}`,
+    apiKey: (overrides.apiKey as string) || "sk-test",
+    accessToken: overrides.accessToken as string | undefined,
+    isActive: true,
+    testStatus: "active",
+    providerSpecificData: {},
+  }) as Promise<{ id: string }>;
+}
+
+function countProviderBlocks(ownedBySequence: string[]): number {
+  const blocks: string[] = [];
+  for (const ownedBy of ownedBySequence) {
+    if (blocks.length === 0 || blocks[blocks.length - 1] !== ownedBy) {
+      blocks.push(ownedBy);
+    }
+  }
+  return blocks.length;
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Exact provider-grouped order: blocks === distinct owned_by
+// ─────────────────────────────────────────────────────────────────────────────
+
+test("catalog /v1/models: exact provider-grouped order (blocks === distinct owned_by)", async () => {
+  // Seed 3 providers with synced models to guarantee fragmentation if unsorted.
+  // The static registry also emits models for active providers, so the catalog
+  // will contain rows from openai, anthropic, and opencode from multiple loops.
+  const conn1 = await seedConnection("openai");
+  const conn2 = await seedConnection("anthropic");
+  const conn3 = await seedConnection("opencode");
+
+  await modelsDb.replaceSyncedAvailableModelsForConnection("openai", (conn1 as any).id, [
+    { id: "gpt-4", name: "GPT-4" },
+    { id: "gpt-3.5-turbo", name: "GPT-3.5 Turbo" },
+  ]);
+  await modelsDb.replaceSyncedAvailableModelsForConnection("anthropic", (conn2 as any).id, [
+    { id: "claude-3-opus", name: "Claude 3 Opus" },
+  ]);
+  await modelsDb.replaceSyncedAvailableModelsForConnection("opencode", (conn3 as any).id, [
+    { id: "kimi-k2", name: "Kimi K2" },
+    { id: "glm-4", name: "GLM-4" },
+  ]);
+
+  const response = await v1ModelsCatalog.getUnifiedModelsResponse(
+    new Request("http://localhost/v1/models?configuredOnly=true")
+  );
+  assert.equal(response.status, 200);
+  const body = (await response.json()) as { data: Array<{ owned_by: string }> };
+
+  // Guarantee rows from all 3 seeded providers are present
+  const ownedByValues = body.data.map((m) => m.owned_by);
+  const distinctOwnedBy = new Set(ownedByValues);
+  assert.ok(distinctOwnedBy.has("openai"), "openai rows present");
+  assert.ok(distinctOwnedBy.has("anthropic"), "anthropic rows present");
+  assert.ok(distinctOwnedBy.has("opencode"), "opencode rows present");
+
+  // Exact invariant: each provider appears in exactly one contiguous block
+  const blockCount = countProviderBlocks(ownedByValues);
+  assert.equal(
+    blockCount,
+    distinctOwnedBy.size,
+    `Fragmented: ${blockCount} blocks for ${distinctOwnedBy.size} distinct providers. ` +
+      `Sequence: ${ownedByValues.join(", ")}`
+  );
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Combo block pinned first
+// ─────────────────────────────────────────────────────────────────────────────
+
+test("catalog /v1/models: combo block appears first", async () => {
+  const conn = await seedConnection("openai");
+  await modelsDb.replaceSyncedAvailableModelsForConnection("openai", (conn as any).id, [
+    { id: "gpt-4", name: "GPT-4" },
+  ]);
+  await combosDb.createCombo({
+    name: "test-combo",
+    modelIds: ["openai/gpt-4"],
+    strategy: "fallback",
+    isActive: true,
+  });
+
+  const response = await v1ModelsCatalog.getUnifiedModelsResponse(
+    new Request("http://localhost/v1/models?configuredOnly=true")
+  );
+  const body = (await response.json()) as { data: Array<{ owned_by: string }> };
+
+  const hasCombo = body.data.some((m) => m.owned_by === "combo");
+  const hasNonCombo = body.data.some((m) => m.owned_by !== "combo");
+  assert.ok(hasCombo, "combo rows present");
+  assert.ok(hasNonCombo, "non-combo rows present");
+
+  const firstNonComboIndex = body.data.findIndex((m) => m.owned_by !== "combo");
+  const lastComboIndex = body.data.map((m) => m.owned_by).lastIndexOf("combo");
+  assert.ok(
+    lastComboIndex < firstNonComboIndex,
+    `Combo block not first: last combo at ${lastComboIndex}, first non-combo at ${firstNonComboIndex}`
+  );
+});
diff --git a/tests/unit/catalog-order-helper.test.ts b/tests/unit/catalog-order-helper.test.ts
new file mode 100644
index 0000000000..f01571d1b6
--- /dev/null
+++ b/tests/unit/catalog-order-helper.test.ts
@@ -0,0 +1,135 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { sortCatalogModelsProviderGrouped } from "../../src/app/api/v1/models/catalogOrder.ts";
+
+test("combo pinning: combos move to front regardless of input or registry order", () => {
+  // Combos are at input positions 1 and 3, and "combo" is not a registry key
+  // (would rank Infinity/unknown without pinning). Asserting they land first
+  // proves pinning overrides both input order and registry precedence.
+  const input = [
+    { id: "openai/gpt-4", owned_by: "openai" },
+    { id: "auto/smart", owned_by: "combo" },
+    { id: "anthropic/claude", owned_by: "anthropic" },
+    { id: "auto/cheap", owned_by: "combo" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  assert.deepEqual(
+    out.map((m) => m.id),
+    ["auto/smart", "auto/cheap", "openai/gpt-4", "anthropic/claude"]
+  );
+});
+
+test("canonical owned_by grouping: oc prefix with opencode owned_by stays contiguous", () => {
+  const input = [
+    { id: "oc/kimi-k2", owned_by: "opencode" },
+    { id: "openai/gpt-4", owned_by: "openai" },
+    { id: "oc/glm-5", owned_by: "opencode" },
+    { id: "openai/gpt-5", owned_by: "openai" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  const keys = out.map((m) => m.owned_by);
+  assert.equal(keys.lastIndexOf("opencode") - keys.indexOf("opencode"), 1);
+  assert.equal(keys.lastIndexOf("openai") - keys.indexOf("openai"), 1);
+});
+
+test("registry precedence over code-unit: qoder before agy (both oauth)", () => {
+  // oauth.ts key order: qoder (idx 3) before agy (idx 4); code-unit: agy < qoder.
+  const input = [
+    { id: "agy/gemini", owned_by: "agy" },
+    { id: "qoder/model", owned_by: "qoder" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  assert.deepEqual(
+    out.map((m) => m.owned_by),
+    ["qoder", "agy"]
+  );
+});
+
+test("registry precedence over code-unit: zed (oauth) before openai (apikey)", () => {
+  // oauth tier precedes apikey tier; code-unit: openai < zed.
+  const input = [
+    { id: "openai/gpt-4", owned_by: "openai" },
+    { id: "zed/model", owned_by: "zed" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  assert.deepEqual(
+    out.map((m) => m.owned_by),
+    ["zed", "openai"]
+  );
+});
+
+test("unknown providers: deterministic code-unit order", () => {
+  const input = [
+    { id: "zzz-unknown/m1", owned_by: "zzz-unknown" },
+    { id: "Zed-unknown/m2", owned_by: "Zed-unknown" },
+    { id: "aaa-unknown/m3", owned_by: "aaa-unknown" },
+    { id: "9nine-unknown/m4", owned_by: "9nine-unknown" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  // Code-unit: '9'(0x39) < 'Z'(0x5A) < 'a'(0x61) < 'z'(0x7A).
+  assert.deepEqual(
+    out.map((m) => m.owned_by),
+    ["9nine-unknown", "Zed-unknown", "aaa-unknown", "zzz-unknown"]
+  );
+});
+
+test("malformed rows: fallback to id-prefix, exact ordered sequence", () => {
+  // Empty id ("") is legal by the Record<string, unknown> type; group key ""
+  // sorts first among unknown fallbacks by code unit. Covers missing owned_by,
+  // empty owned_by, slashless id, and empty id, plus stability within a group.
+  const input = [
+    { id: "openai/gpt-4", owned_by: "openai" }, // registry group
+    { id: "weird/model", owned_by: "" }, // empty owned_by → prefix "weird"
+    { id: "slashless", owned_by: "" }, // empty owned_by, no slash → "slashless"
+    { id: "openai/gpt-5", owned_by: "openai" }, // registry group
+    { id: "weird/model2" }, // missing owned_by → prefix "weird"
+    { id: "", owned_by: "" }, // empty id → group key ""
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  // openai (finite registry rank) first in input order; then unknown fallbacks
+  // by code-unit of group key: "" < "slashless" < "weird"; stable within "weird".
+  assert.deepEqual(
+    out.map((m) => m.id),
+    ["openai/gpt-4", "openai/gpt-5", "", "slashless", "weird/model", "weird/model2"]
+  );
+});
+
+test("stability: equal-ID twins preserve input order", () => {
+  const input = [
+    { id: "openai/gpt-4", owned_by: "openai", subtype: "chat" },
+    { id: "openai/gpt-4", owned_by: "openai", subtype: "speech" },
+    { id: "openai/gpt-3.5", owned_by: "openai" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  assert.equal(out[0].subtype, "chat");
+  assert.equal(out[1].subtype, "speech");
+  assert.equal(out[2].id, "openai/gpt-3.5");
+});
+
+test("non-mutation: input array and elements untouched", () => {
+  const input = [
+    { id: "openai/gpt-4", owned_by: "openai" },
+    { id: "anthropic/claude", owned_by: "anthropic" },
+  ];
+  const snapshot = JSON.parse(JSON.stringify(input));
+  const out = sortCatalogModelsProviderGrouped(input);
+  assert.deepEqual(input, snapshot);
+  assert.notEqual(out, input);
+  assert.equal(out.length, input.length);
+});
+
+test("no drops or dupes: every row present exactly once", () => {
+  const input = [
+    { id: "openai/gpt-4", owned_by: "openai" },
+    { id: "auto/x", owned_by: "combo" },
+    { id: "anthropic/claude", owned_by: "anthropic" },
+    { id: "weird/m", owned_by: "" },
+    { id: "openai/gpt-5", owned_by: "openai" },
+  ];
+  const out = sortCatalogModelsProviderGrouped(input);
+  assert.equal(out.length, input.length);
+  assert.deepEqual(
+    out.map((m) => m.id).sort(),
+    input.map((m) => m.id).sort()
+  );
+});