diff --git a/extensions/extensions.json b/extensions/extensions.json
index e38c08ca2e..0c7f5d79c3 100644
--- a/extensions/extensions.json
+++ b/extensions/extensions.json
@@ -26,6 +26,7 @@
   "Lily/MoreEvents",
   "NexusKitten/moremotion",
   "CubesterYT/WindowControls",
+  "veggiecan/browserfullscreen",
   "navigator",
   "battery",
   "TheShovel/CustomStyles",
diff --git a/extensions/veggiecan/browserfullscreen.js b/extensions/veggiecan/browserfullscreen.js
new file mode 100644
index 0000000000..7aa3f93b3d
--- /dev/null
+++ b/extensions/veggiecan/browserfullscreen.js
@@ -0,0 +1,103 @@
+// Name: Browser Fullscreen
+// ID: fullscreen0419
+// Description: Enter and exit fullscreen mode.
+// By: Veggiecan0419
+
+(function (Scratch) {
+  "use strict";
+  const icon =
+    "data:image/svg+xml;base64,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";
+
+  window.addEventListener("fullscreenchange", () => {
+    Scratch.vm.runtime.startHats("fullscreen0419_whenfullscreen", {
+      ENABLED: document.fullscreenElement === null ? "exited" : "entered",
+    });
+  });
+
+  class FullscreenExtension {
+    getInfo() {
+      return {
+        id: "fullscreen0419",
+        color1: "#F39016",
+        color2: "#C77612",
+        color3: "#9D5D0E",
+        blockIconURI: icon,
+        name: "Browser Fullscreen",
+        blocks: [
+          {
+            opcode: "fullscreen",
+            blockType: Scratch.BlockType.COMMAND,
+            text: "[ACTION] fullscreen",
+            arguments: {
+              ACTION: {
+                type: Scratch.ArgumentType.STRING,
+                menu: "fullscreenMenu",
+                defaultValue: "enter",
+              },
+            },
+          },
+          {
+            opcode: "isInFullscreen",
+            blockType: Scratch.BlockType.BOOLEAN,
+            text: "in browser fullscreen?",
+            arguments: {},
+          },
+          {
+            opcode: "whenfullscreen",
+            blockType: Scratch.BlockType.EVENT,
+            text: "when browser fullscreen [ENABLED]",
+            isEdgeActivated: false,
+            arguments: {
+              ENABLED: {
+                type: Scratch.ArgumentType.STRING,
+                menu: "whenfullscreenMenu",
+              },
+            },
+          },
+        ],
+        menus: {
+          fullscreenMenu: {
+            acceptReporters: true,
+            items: [
+              {
+                text: "enter",
+                value: "enter",
+              },
+              {
+                text: "exit",
+                value: "exit",
+              },
+            ],
+          },
+          whenfullscreenMenu: {
+            // Used for startHats filtering.
+            acceptReporters: false,
+            items: [
+              {
+                text: "entered",
+                value: "entered",
+              },
+              {
+                text: "exited",
+                value: "exited",
+              },
+            ],
+          },
+        },
+      };
+    }
+    fullscreen(args) {
+      const action = args.ACTION;
+      if (action === "enter") {
+        document.documentElement.requestFullscreen();
+      } else if (action === "exit") {
+        document.exitFullscreen();
+      }
+    }
+    isInFullscreen() {
+      return document.fullscreenElement !== null;
+    }
+  }
+
+  Scratch.extensions.register(new FullscreenExtension());
+})(Scratch);