diff --git a/packages/opencode/src/cli/cmd/tui/app.tsx b/packages/opencode/src/cli/cmd/tui/app.tsx
index 0d5aefe7bc..bec17d48ef 100644
--- a/packages/opencode/src/cli/cmd/tui/app.tsx
+++ b/packages/opencode/src/cli/cmd/tui/app.tsx
@@ -3,6 +3,7 @@ import { Clipboard } from "@tui/util/clipboard"
 import { TextAttributes } from "@opentui/core"
 import { RouteProvider, useRoute } from "@tui/context/route"
 import { Switch, Match, createEffect, untrack, ErrorBoundary, createSignal, onMount, batch, Show, on } from "solid-js"
+import { win32DisableProcessedInput, win32IgnoreCtrlC, win32EnforceCtrlCGuard } from "./win32"
 import { Installation } from "@/installation"
 import { Flag } from "@/flag/flag"
 import { DialogProvider, useDialog } from "@tui/ui/dialog"
@@ -110,7 +111,15 @@ export function tui(input: {
 }) {
   // promise to prevent immediate exit
   return new Promise<void>(async (resolve) => {
+    win32DisableProcessedInput()
+    win32IgnoreCtrlC()
+
     const mode = await getTerminalBackgroundColor()
+
+    // Re-clear after getTerminalBackgroundColor() — setRawMode(false) restores
+    // the original console mode which re-enables ENABLE_PROCESSED_INPUT.
+    win32DisableProcessedInput()
+
     const onExit = async () => {
       await input.onExit?.()
       resolve()
@@ -238,6 +247,10 @@ function App() {
 
   const args = useArgs()
   onMount(() => {
+    // opentui reconfigures console mode via native calls which re-enable
+    // ENABLE_PROCESSED_INPUT. Poll and re-clear it so the parent `bun run`
+    // wrapper isn't killed by CTRL_C_EVENT.
+    win32EnforceCtrlCGuard()
     batch(() => {
       if (args.agent) local.agent.set(args.agent)
       if (args.model) {
diff --git a/packages/opencode/src/cli/cmd/tui/thread.ts b/packages/opencode/src/cli/cmd/tui/thread.ts
index 2ea49ff6b2..87987a45f0 100644
--- a/packages/opencode/src/cli/cmd/tui/thread.ts
+++ b/packages/opencode/src/cli/cmd/tui/thread.ts
@@ -9,6 +9,7 @@ import { Log } from "@/util/log"
 import { withNetworkOptions, resolveNetworkOptions } from "@/cli/network"
 import type { Event } from "@opencode-ai/sdk/v2"
 import type { EventSource } from "./context/sdk"
+import { win32DisableProcessedInput } from "./win32"
 
 declare global {
   const OPENCODE_WORKER_PATH: string
@@ -77,6 +78,10 @@ export const TuiThreadCommand = cmd({
         describe: "agent to use",
       }),
   handler: async (args) => {
+    // Must be the very first thing — disables CTRL_C_EVENT before any Worker
+    // spawn or async work so the OS cannot kill the process group.
+    win32DisableProcessedInput()
+
     if (args.fork && !args.continue && !args.session) {
       UI.error("--fork requires --continue or --session")
       process.exit(1)
diff --git a/packages/opencode/src/cli/cmd/tui/win32.ts b/packages/opencode/src/cli/cmd/tui/win32.ts
new file mode 100644
index 0000000000..ddd8913f19
--- /dev/null
+++ b/packages/opencode/src/cli/cmd/tui/win32.ts
@@ -0,0 +1,86 @@
+import { dlopen, ptr } from "bun:ffi"
+
+const STD_INPUT_HANDLE = -10
+const ENABLE_PROCESSED_INPUT = 0x0001
+
+const kernel = () =>
+  dlopen("kernel32.dll", {
+    GetStdHandle: { args: ["i32"], returns: "ptr" },
+    GetConsoleMode: { args: ["ptr", "ptr"], returns: "i32" },
+    SetConsoleMode: { args: ["ptr", "u32"], returns: "i32" },
+    SetConsoleCtrlHandler: { args: ["ptr", "i32"], returns: "i32" },
+  })
+
+let k32: ReturnType<typeof kernel> | undefined
+
+function load() {
+  if (process.platform !== "win32") return false
+  try {
+    k32 ??= kernel()
+    return true
+  } catch {
+    return false
+  }
+}
+
+/**
+ * Clear ENABLE_PROCESSED_INPUT on the console stdin handle.
+ */
+export function win32DisableProcessedInput() {
+  if (process.platform !== "win32") return
+  if (!process.stdin.isTTY) return
+  if (!load()) return
+
+  const handle = k32!.symbols.GetStdHandle(STD_INPUT_HANDLE)
+  const buf = new Uint32Array(1)
+  if (k32!.symbols.GetConsoleMode(handle, ptr(buf)) === 0) return
+
+  const mode = buf[0]!
+  if ((mode & ENABLE_PROCESSED_INPUT) === 0) return
+  k32!.symbols.SetConsoleMode(handle, mode & ~ENABLE_PROCESSED_INPUT)
+}
+
+/**
+ * Tell Windows to ignore CTRL_C_EVENT for this process.
+ *
+ * SetConsoleCtrlHandler(NULL, TRUE) makes the process ignore Ctrl+C
+ * signals at the OS level. Belt-and-suspenders alongside disabling
+ * ENABLE_PROCESSED_INPUT.
+ */
+export function win32IgnoreCtrlC() {
+  if (process.platform !== "win32") return
+  if (!process.stdin.isTTY) return
+  if (!load()) return
+
+  k32!.symbols.SetConsoleCtrlHandler(null, 1)
+}
+
+/**
+ * Continuously enforce ENABLE_PROCESSED_INPUT=off on the console.
+ *
+ * opentui reconfigures the console mode through native calls (not
+ * process.stdin.setRawMode) so we cannot intercept them. Instead we
+ * poll at a low frequency and re-clear the flag when needed.
+ *
+ * Because ENABLE_PROCESSED_INPUT is a console-level flag (not per-process),
+ * keeping it cleared protects every process attached to this console,
+ * including the parent `bun run` wrapper that we can't otherwise control.
+ *
+ * The fast-path (GetConsoleMode + bitmask check) is sub-microsecond;
+ * SetConsoleMode only fires when something re-enabled the flag.
+ */
+export function win32EnforceCtrlCGuard() {
+  if (process.platform !== "win32") return
+  if (!process.stdin.isTTY) return
+  if (!load()) return
+
+  const handle = k32!.symbols.GetStdHandle(STD_INPUT_HANDLE)
+  const buf = new Uint32Array(1)
+
+  setInterval(() => {
+    if (k32!.symbols.GetConsoleMode(handle, ptr(buf)) === 0) return
+    const mode = buf[0]!
+    if ((mode & ENABLE_PROCESSED_INPUT) === 0) return
+    k32!.symbols.SetConsoleMode(handle, mode & ~ENABLE_PROCESSED_INPUT)
+  }, 100)
+}
diff --git a/packages/opencode/src/index.ts b/packages/opencode/src/index.ts
index 6dc5e99e91..96759cc139 100644
--- a/packages/opencode/src/index.ts
+++ b/packages/opencode/src/index.ts
@@ -26,6 +26,15 @@ import { EOL } from "os"
 import { WebCommand } from "./cli/cmd/web"
 import { PrCommand } from "./cli/cmd/pr"
 import { SessionCommand } from "./cli/cmd/session"
+import { win32DisableProcessedInput, win32IgnoreCtrlC } from "./cli/cmd/tui/win32"
+
+// Disable Windows CTRL_C_EVENT as early as possible. When running under
+// `bun run` (e.g. `bun dev`), the parent bun process shares this console
+// and would be killed by the OS before any JS signal handler fires.
+win32DisableProcessedInput()
+// Belt-and-suspenders: even if something re-enables ENABLE_PROCESSED_INPUT
+// later (opentui raw mode, libuv, etc.), ignore the generated event.
+win32IgnoreCtrlC()
 
 process.on("unhandledRejection", (e) => {
   Log.Default.error("rejection", {