diff --git a/packages/desktop/electron-builder.config.test.ts b/packages/desktop/electron-builder.config.test.ts
index e0052557b3e..353dd402d96 100644
--- a/packages/desktop/electron-builder.config.test.ts
+++ b/packages/desktop/electron-builder.config.test.ts
@@ -88,6 +88,22 @@ test("legacy Linux launcher stays hidden", async () => {
   expect(desktop).toContain("NoDisplay=true")
 })
 
+test.each(channels)("macOS icon format for $channel", ({ channel }) => {
+  const config = load(channel)
+  expect(config.mac?.icon).toBe(channel === "prod" ? "resources/icons/icon.icon" : "resources/icons/icon.icns")
+  expect(config.dmg?.icon).toBe(channel === "prod" ? "resources/icons/icon.icns" : undefined)
+  // The prod override must keep the rest of the shared macOS settings.
+  expect(config.mac?.target).toEqual(["dmg", "zip"])
+  expect(config.mac?.extendInfo?.NSMicrophoneUsageDescription).toBeTruthy()
+})
+
+test("the production Icon Composer package references its bundled artwork", async () => {
+  const icon = await Bun.file(path.join(import.meta.dirname, "icons/prod/icon.icon/icon.json")).json()
+  expect(icon["supported-platforms"]).toEqual({ squares: ["macOS"] })
+  const image = icon.groups[0].layers[0]["image-name"]
+  expect(await Bun.file(path.join(import.meta.dirname, "icons/prod/icon.icon/Assets", image)).exists()).toBe(true)
+})
+
 test("shared packaging defaults", async () => {
   const config = load("dev")
   // Packaging runs in secretless build jobs; the release workflow signs and notarizes afterwards.
diff --git a/packages/desktop/electron-builder.config.ts b/packages/desktop/electron-builder.config.ts
index 7c090083cba..5d4270cdf08 100644
--- a/packages/desktop/electron-builder.config.ts
+++ b/packages/desktop/electron-builder.config.ts
@@ -1,4 +1,4 @@
-import { readdir, stat } from "node:fs/promises"
+import { copyFile, readdir, stat } from "node:fs/promises"
 import path from "node:path"
 import { fileURLToPath } from "node:url"
 
@@ -126,6 +126,11 @@ const getBase = (appId: string): Configuration => {
 
       if ((await stat(version)).size === 0) throw new Error(`Bundled CLI version must be a non-empty file: ${version}`)
 
+      // With an Icon Composer mac.icon, electron-builder bundles the ICNS that actool generates as the pre-macOS 26
+      // fallback. That one tops out at 256px and draws a light ring around the squircle, so ship ours instead.
+      if (context.electronPlatformName === "darwin")
+        await copyFile(path.join(packageDir, "resources/icons/icon.icns"), path.join(resources, "icon.icns"))
+
       if (context.electronPlatformName !== "win32") return
 
       const prebuilds = path.join(
@@ -245,6 +250,11 @@ export function getConfig() {
         appId,
         productName: "OpenCode",
         protocols: { name: "OpenCode", schemes: ["opencode"] },
+        // An Icon Composer package compiles to Assets.car, which macOS 26 and later draw the app icon from
+        // (Dock, Finder, system dialogs and the system icon styles). Older macOS keeps using the ICNS.
+        mac: { ...base.mac, icon: "resources/icons/icon.icon" },
+        // The DMG volume icon would otherwise use the same actool-generated ICNS.
+        dmg: { icon: "resources/icons/icon.icns" },
         publish: {
           provider: "generic",
           url: "https://opencode.ai/update/api/latest/desktop/opencode/",
diff --git a/packages/desktop/icons/prod/icon.icon/Assets/icon.png b/packages/desktop/icons/prod/icon.icon/Assets/icon.png
new file mode 100644
index 00000000000..11fa40f03f6
Binary files /dev/null and b/packages/desktop/icons/prod/icon.icon/Assets/icon.png differ
diff --git a/packages/desktop/icons/prod/icon.icon/icon.json b/packages/desktop/icons/prod/icon.icon/icon.json
new file mode 100644
index 00000000000..3845b88ea9e
--- /dev/null
+++ b/packages/desktop/icons/prod/icon.icon/icon.json
@@ -0,0 +1,25 @@
+{
+  "groups": [
+    {
+      "name": "OpenCode",
+      "layers": [
+        {
+          "name": "OpenCode",
+          "image-name": "icon.png",
+          "glass": false
+        }
+      ],
+      "shadow": {
+        "kind": "none",
+        "opacity": 0
+      },
+      "translucency": {
+        "enabled": false,
+        "value": 0.5
+      }
+    }
+  ],
+  "supported-platforms": {
+    "squares": ["macOS"]
+  }
+}