diff --git a/macos/Sources/Ghostty/Ghostty.App.swift b/macos/Sources/Ghostty/Ghostty.App.swift
index aff3edbc7..4788a4376 100644
--- a/macos/Sources/Ghostty/Ghostty.App.swift
+++ b/macos/Sources/Ghostty/Ghostty.App.swift
@@ -588,6 +588,9 @@ extension Ghostty {
             case GHOSTTY_ACTION_RING_BELL:
                 ringBell(app, target: target)
 
+            case GHOSTTY_ACTION_READONLY:
+                setReadonly(app, target: target, v: action.action.readonly)
+
             case GHOSTTY_ACTION_CHECK_FOR_UPDATES:
                 checkForUpdates(app)
                 
@@ -1010,6 +1013,31 @@ extension Ghostty {
             }
         }
 
+        private static func setReadonly(
+            _ app: ghostty_app_t,
+            target: ghostty_target_s,
+            v: ghostty_action_readonly_e) {
+            switch (target.tag) {
+            case GHOSTTY_TARGET_APP:
+                Ghostty.logger.warning("set readonly does nothing with an app target")
+                return
+
+            case GHOSTTY_TARGET_SURFACE:
+                guard let surface = target.target.surface else { return }
+                guard let surfaceView = self.surfaceView(from: surface) else { return }
+                NotificationCenter.default.post(
+                    name: .ghosttyDidChangeReadonly,
+                    object: surfaceView,
+                    userInfo: [
+                        SwiftUI.Notification.Name.ReadonlyKey: v == GHOSTTY_READONLY_ON,
+                    ]
+                )
+
+            default:
+                assertionFailure()
+            }
+        }
+
         private static func moveTab(
             _ app: ghostty_app_t,
             target: ghostty_target_s,
diff --git a/macos/Sources/Ghostty/Package.swift b/macos/Sources/Ghostty/Package.swift
index 4b3eb60aa..258857e8e 100644
--- a/macos/Sources/Ghostty/Package.swift
+++ b/macos/Sources/Ghostty/Package.swift
@@ -391,6 +391,10 @@ extension Notification.Name {
 
     /// Ring the bell
     static let ghosttyBellDidRing = Notification.Name("com.mitchellh.ghostty.ghosttyBellDidRing")
+
+    /// Readonly mode changed
+    static let ghosttyDidChangeReadonly = Notification.Name("com.mitchellh.ghostty.didChangeReadonly")
+    static let ReadonlyKey = ghosttyDidChangeReadonly.rawValue + ".readonly"
     static let ghosttyCommandPaletteDidToggle = Notification.Name("com.mitchellh.ghostty.commandPaletteDidToggle")
 
     /// Toggle maximize of current window
diff --git a/macos/Sources/Ghostty/SurfaceView.swift b/macos/Sources/Ghostty/SurfaceView.swift
index ba678db59..c027162ab 100644
--- a/macos/Sources/Ghostty/SurfaceView.swift
+++ b/macos/Sources/Ghostty/SurfaceView.swift
@@ -104,6 +104,11 @@ extension Ghostty {
                 }
                 .ghosttySurfaceView(surfaceView)
                 
+                // Readonly indicator badge
+                if surfaceView.readonly {
+                    ReadonlyBadge()
+                }
+                
                 // Progress report
                 if let progressReport = surfaceView.progressReport, progressReport.state != .remove {
                     VStack(spacing: 0) {
@@ -757,6 +762,48 @@ extension Ghostty {
         }
     }
 
+    // MARK: Readonly Badge
+    
+    /// A badge overlay that indicates a surface is in readonly mode.
+    /// Positioned in the top-right corner and styled to be noticeable but unobtrusive.
+    struct ReadonlyBadge: View {
+        private let badgeColor = Color(hue: 0.08, saturation: 0.5, brightness: 0.8)
+        
+        var body: some View {
+            VStack {
+                HStack {
+                    Spacer()
+                    
+                    HStack(spacing: 5) {
+                        Image(systemName: "eye.fill")
+                            .font(.system(size: 12))
+                        Text("Read-only")
+                            .font(.system(size: 12, weight: .medium))
+                    }
+                    .padding(.horizontal, 8)
+                    .padding(.vertical, 4)
+                    .background(badgeBackground)
+                    .foregroundStyle(badgeColor)
+                }
+                .padding(8)
+                
+                Spacer()
+            }
+            .allowsHitTesting(false)
+            .accessibilityElement(children: .ignore)
+            .accessibilityLabel("Read-only terminal")
+        }
+        
+        private var badgeBackground: some View {
+            RoundedRectangle(cornerRadius: 6)
+                .fill(.regularMaterial)
+                .overlay(
+                    RoundedRectangle(cornerRadius: 6)
+                        .strokeBorder(Color.orange.opacity(0.6), lineWidth: 1.5)
+                )
+        }
+    }
+
     #if canImport(AppKit)
     /// When changing the split state, or going full screen (native or non), the terminal view
     /// will lose focus. There has to be some nice SwiftUI-native way to fix this but I can't
diff --git a/macos/Sources/Ghostty/SurfaceView_AppKit.swift b/macos/Sources/Ghostty/SurfaceView_AppKit.swift
index 130df6f44..d8670e644 100644
--- a/macos/Sources/Ghostty/SurfaceView_AppKit.swift
+++ b/macos/Sources/Ghostty/SurfaceView_AppKit.swift
@@ -123,6 +123,9 @@ extension Ghostty {
         /// True when the bell is active. This is set inactive on focus or event.
         @Published private(set) var bell: Bool = false
 
+        /// True when the surface is in readonly mode.
+        @Published private(set) var readonly: Bool = false
+
         // An initial size to request for a window. This will only affect
         // then the view is moved to a new window.
         var initialSize: NSSize? = nil
@@ -333,6 +336,11 @@ extension Ghostty {
                 selector: #selector(ghosttyBellDidRing(_:)),
                 name: .ghosttyBellDidRing,
                 object: self)
+            center.addObserver(
+                self,
+                selector: #selector(ghosttyDidChangeReadonly(_:)),
+                name: .ghosttyDidChangeReadonly,
+                object: self)
             center.addObserver(
                 self,
                 selector: #selector(windowDidChangeScreen),
@@ -703,6 +711,11 @@ extension Ghostty {
             bell = true
         }
 
+        @objc private func ghosttyDidChangeReadonly(_ notification: SwiftUI.Notification) {
+            guard let value = notification.userInfo?[SwiftUI.Notification.Name.ReadonlyKey] as? Bool else { return }
+            readonly = value
+        }
+
         @objc private func windowDidChangeScreen(notification: SwiftUI.Notification) {
             guard let window = self.window else { return }
             guard let object = notification.object as? NSWindow, window == object else { return }
diff --git a/macos/Sources/Ghostty/SurfaceView_UIKit.swift b/macos/Sources/Ghostty/SurfaceView_UIKit.swift
index 09c41c0b5..568a93314 100644
--- a/macos/Sources/Ghostty/SurfaceView_UIKit.swift
+++ b/macos/Sources/Ghostty/SurfaceView_UIKit.swift
@@ -43,6 +43,9 @@ extension Ghostty {
         
         // The current search state. When non-nil, the search overlay should be shown.
         @Published var searchState: SearchState? = nil
+        
+        /// True when the surface is in readonly mode.
+        @Published private(set) var readonly: Bool = false
 
         // Returns sizing information for the surface. This is the raw C
         // structure because I'm lazy.