diff --git a/bin/cli/commands/dashboard.mjs b/bin/cli/commands/dashboard.mjs
index ff7d8c7b01..44d2da1df9 100644
--- a/bin/cli/commands/dashboard.mjs
+++ b/bin/cli/commands/dashboard.mjs
@@ -1,17 +1,22 @@
 import { execFile } from "node:child_process";
 import { t } from "../i18n.mjs";
 
+function parsePort(value, fallback) {
+  const parsed = parseInt(String(value), 10);
+  return Number.isFinite(parsed) && parsed > 0 && parsed <= 65535 ? parsed : fallback;
+}
+
 export function registerDashboard(program) {
   program
     .command("dashboard")
     .description(t("dashboard.description"))
     .option("--url", t("dashboard.urlOnly"))
-    .option("--port <port>", "Port the server is running on", "20128")
+    .option("--port <port>", "Port the server is running on")
     .option("--tui", t("dashboard.tui") || "Open interactive TUI dashboard (terminal UI)")
     .action(async (opts, cmd) => {
       if (opts.tui) {
         const globalOpts = cmd.optsWithGlobals();
-        const port = opts.port ? parseInt(String(opts.port), 10) : 20128;
+        const port = parsePort(opts.port ?? process.env.PORT ?? "20128", 20128);
         const baseUrl = globalOpts.baseUrl ?? `http://localhost:${port}`;
         const apiKey = globalOpts.apiKey ?? null;
         const { startInteractiveTui } = await import("../tui/Dashboard.jsx");
@@ -24,7 +29,7 @@ export function registerDashboard(program) {
 }
 
 export async function runDashboardCommand(opts = {}) {
-  const port = opts.port ? parseInt(String(opts.port), 10) : 20128;
+  const port = parsePort(opts.port ?? process.env.PORT ?? "20128", 20128);
   const dashboardUrl = `http://localhost:${port}`;
 
   if (opts.url) {
diff --git a/changelog.d/fixes/7049-dashboard-port-env-fallback.md b/changelog.d/fixes/7049-dashboard-port-env-fallback.md
new file mode 100644
index 0000000000..b3c51761ea
--- /dev/null
+++ b/changelog.d/fixes/7049-dashboard-port-env-fallback.md
@@ -0,0 +1 @@
+- **fix(cli):** `omniroute dashboard` (no `--port` flag) now respects `PORT` from the environment instead of always opening `localhost:20128`, matching `serve`/`launch` precedence (`--port` > `PORT` env > `20128` default) (#7049 — thanks @kaon0388v1).
diff --git a/tests/unit/cli-dashboard-port.test.ts b/tests/unit/cli-dashboard-port.test.ts
new file mode 100644
index 0000000000..75a22b2f2b
--- /dev/null
+++ b/tests/unit/cli-dashboard-port.test.ts
@@ -0,0 +1,75 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+/**
+ * Replicate the parsePort + port resolution logic from bin/cli/commands/dashboard.mjs
+ * to verify that PORT env var is respected when --port is not passed (mirrors
+ * tests/unit/cli-serve-port.test.ts's convention for serve.mjs).
+ */
+function parsePort(value: string | undefined, fallback: number): number {
+  const parsed = parseInt(String(value), 10);
+  return Number.isFinite(parsed) && parsed > 0 && parsed <= 65535 ? parsed : fallback;
+}
+
+function resolvePort(optsPort: string | undefined, envPort: string | undefined): number {
+  return parsePort(optsPort ?? envPort ?? "20128", 20128);
+}
+
+test("dashboard port: uses --port flag when explicitly provided, overriding env", () => {
+  const port = resolvePort("3000", "9999");
+  assert.equal(port, 3000);
+});
+
+test("dashboard port: falls back to PORT env var when --port is not provided", () => {
+  const port = resolvePort(undefined, "20129");
+  assert.equal(port, 20129);
+});
+
+test("dashboard port: falls back to 20128 when neither --port nor PORT env var is set", () => {
+  const port = resolvePort(undefined, undefined);
+  assert.equal(port, 20128);
+});
+
+test("dashboard port: invalid --port (non-numeric) falls back to 20128", () => {
+  const port = resolvePort("abc", undefined);
+  assert.equal(port, 20128);
+});
+
+test("dashboard port: --port 0 (out of range) falls back to 20128", () => {
+  const port = resolvePort("0", undefined);
+  assert.equal(port, 20128);
+});
+
+test("dashboard port: --port 70000 (out of range) falls back to 20128", () => {
+  const port = resolvePort("70000", undefined);
+  assert.equal(port, 20128);
+});
+
+test("dashboard URL generation: http://localhost:<port> built correctly for a custom port", () => {
+  const port = resolvePort(undefined, "31337");
+  assert.equal(`http://localhost:${port}`, "http://localhost:31337");
+});
+
+test("dashboard command: --port option has no Commander default", async () => {
+  const fs = await import("node:fs");
+  const path = await import("node:path");
+  const dashboardSource = fs.readFileSync(
+    path.resolve(import.meta.dirname, "../../bin/cli/commands/dashboard.mjs"),
+    "utf-8",
+  );
+  // Ensure the option does NOT carry a baked-in Commander default (third arg).
+  assert.match(
+    dashboardSource,
+    /\.option\("--port <port>",\s*"Port the server is running on"\)/,
+  );
+});
+
+test("dashboard command: source references process.env.PORT (env-fallback regression guard)", async () => {
+  const fs = await import("node:fs");
+  const path = await import("node:path");
+  const dashboardSource = fs.readFileSync(
+    path.resolve(import.meta.dirname, "../../bin/cli/commands/dashboard.mjs"),
+    "utf-8",
+  );
+  assert.match(dashboardSource, /process\.env\.PORT/);
+});