diff --git a/libcef/browser/chrome/extensions/chrome_extension_util.cc b/libcef/browser/chrome/extensions/chrome_extension_util.cc
index 3bee3ad00..48620e3cb 100644
--- a/libcef/browser/chrome/extensions/chrome_extension_util.cc
+++ b/libcef/browser/chrome/extensions/chrome_extension_util.cc
@@ -64,4 +64,12 @@ bool GetAlloyTabById(int tab_id,
   return false;
 }
 
+bool IsAlloyContents(content::WebContents* contents, bool primary_only) {
+  auto browser = CefBrowserHostBase::GetBrowserForContents(contents);
+  if (browser && browser->IsAlloyStyle()) {
+    return !primary_only || browser->GetWebContents() == contents;
+  }
+  return false;
+}
+
 }  // namespace cef
diff --git a/libcef/browser/chrome/extensions/chrome_extension_util.h b/libcef/browser/chrome/extensions/chrome_extension_util.h
index 2f6873190..74a22cd5f 100644
--- a/libcef/browser/chrome/extensions/chrome_extension_util.h
+++ b/libcef/browser/chrome/extensions/chrome_extension_util.h
@@ -21,6 +21,10 @@ bool GetAlloyTabById(int tab_id,
                      bool include_incognito,
                      content::WebContents** contents);
 
+// Returns true if |contents| is owned by an Alloy style CefBrowserHost.
+// If |primary_only| is false then guest contents will also be matched.
+bool IsAlloyContents(content::WebContents* contents, bool primary_only);
+
 }  // namespace cef
 
 #endif  // CEF_LIBCEF_BROWSER_CHROME_EXTENSIONS_CHROME_EXTENSION_UTIL_H_
diff --git a/patch/patch.cfg b/patch/patch.cfg
index 89d2a5845..e15826db3 100644
--- a/patch/patch.cfg
+++ b/patch/patch.cfg
@@ -257,6 +257,11 @@ patches = [
     # https://github.com/chromiumembedded/cef/issues/2969
     'name': 'chrome_browser_context_menus',
   },
+  {
+    # Support DevTools windows with Chrome runtime Alloy style OSR.
+    # https://github.com/chromiumembedded/cef/issues/3681
+    'name': 'chrome_browser_devtools_osr',
+  },
   {
     # Support use of chrome native dialogs with CEF runtimes.
     # - Adds support for FileSelectHelper and SelectFileDialog interception.
diff --git a/patch/patches/chrome_browser_devtools_osr.patch b/patch/patches/chrome_browser_devtools_osr.patch
new file mode 100644
index 000000000..9f1760902
--- /dev/null
+++ b/patch/patches/chrome_browser_devtools_osr.patch
@@ -0,0 +1,36 @@
+diff --git chrome/browser/devtools/chrome_devtools_manager_delegate.cc chrome/browser/devtools/chrome_devtools_manager_delegate.cc
+index 19c2d39b6aa73..099dcb71a6373 100644
+--- chrome/browser/devtools/chrome_devtools_manager_delegate.cc
++++ chrome/browser/devtools/chrome_devtools_manager_delegate.cc
+@@ -13,6 +13,7 @@
+ #include "base/strings/utf_string_conversions.h"
+ #include "build/build_config.h"
+ #include "build/chromeos_buildflags.h"
++#include "cef/libcef/features/features.h"
+ #include "chrome/browser/browser_features.h"
+ #include "chrome/browser/devtools/chrome_devtools_session.h"
+ #include "chrome/browser/devtools/device/android_device_manager.h"
+@@ -66,6 +67,10 @@
+ #include "ash/constants/ash_switches.h"
+ #endif
+ 
++#if BUILDFLAG(ENABLE_CEF)
++#include "cef/libcef/browser/chrome/extensions/chrome_extension_util.h"
++#endif
++
+ using content::DevToolsAgentHost;
+ 
+ const char ChromeDevToolsManagerDelegate::kTypeApp[] = "app";
+@@ -246,6 +251,12 @@ std::string ChromeDevToolsManagerDelegate::GetTargetType(
+     return DevToolsAgentHost::kTypePage;
+   }
+ 
++#if BUILDFLAG(ENABLE_CEF)
++  if (cef::IsAlloyContents(web_contents, /*primary_only=*/true)) {
++    return DevToolsAgentHost::kTypePage;
++  }
++#endif
++
+   return DevToolsAgentHost::kTypeOther;
+ }
+