diff --git a/src/headers/content-security-policy.ts b/src/headers/content-security-policy.ts
index 25de496..481e8fd 100644
--- a/src/headers/content-security-policy.ts
+++ b/src/headers/content-security-policy.ts
@@ -76,13 +76,18 @@ export const contentSecurityPolicy = (
       ];
 
       if (typeof value === "boolean") {
-        return `${directive}`;
+        if (value) {
+          return `${directive}`;
+        }
+
+        return "";
       }
 
       const directiveValue = Array.isArray(value) ? value.join(" ") : value;
 
       return `${directive} ${directiveValue}`;
     })
+    .filter(Boolean)
     .join(";");
 
   context.response.headers.set("Content-Security-Policy", header);
diff --git a/tests/headers/content-security-policy.test.ts b/tests/headers/content-security-policy.test.ts
index 83b7e81..e50fec9 100644
--- a/tests/headers/content-security-policy.test.ts
+++ b/tests/headers/content-security-policy.test.ts
@@ -19,6 +19,28 @@ beforeAll(() => {
     context.text(StatusCode.OK, "Hello, World!");
   });
 
+  server.app.get("/upgrade-insecure-requests/true", (context) => {
+    contentSecurityPolicy(context, {
+      directives: {
+        defaultSrc: ["'self'"],
+        upgradeInsecureRequests: true,
+      },
+    });
+
+    context.text(StatusCode.OK, "Hello, World!");
+  });
+
+  server.app.get("/upgrade-insecure-requests/false", (context) => {
+    contentSecurityPolicy(context, {
+      directives: {
+        defaultSrc: ["'self'"],
+        upgradeInsecureRequests: false,
+      },
+    });
+
+    context.text(StatusCode.OK, "Hello, World!");
+  });
+
   server.start();
 });
 
@@ -39,4 +61,36 @@ describe("headers - content-security-policy", () => {
       "default-src 'self';script-src 'self' https://example.com",
     );
   });
+
+  it("should set security headers with upgrade-insecure-requests", async () => {
+    const response = await fetch(
+      server.url("/upgrade-insecure-requests/true"),
+      {
+        method: "GET",
+      },
+    );
+
+    // drain response to ensure no memory leak
+    await response.text();
+
+    expect(response.headers.get("Content-Security-Policy")).toEqual(
+      "default-src 'self';upgrade-insecure-requests",
+    );
+  });
+
+  it("should not set security headers with upgrade-insecure-requests", async () => {
+    const response = await fetch(
+      server.url("/upgrade-insecure-requests/false"),
+      {
+        method: "GET",
+      },
+    );
+
+    // drain response to ensure no memory leak
+    await response.text();
+
+    expect(response.headers.get("Content-Security-Policy")).toEqual(
+      "default-src 'self'",
+    );
+  });
 });