diff --git a/crates/cli-support/src/js/js2rust.rs b/crates/cli-support/src/js/js2rust.rs
index 5382a9af..67ce0694 100644
--- a/crates/cli-support/src/js/js2rust.rs
+++ b/crates/cli-support/src/js/js2rust.rs
@@ -259,7 +259,26 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
                 return Ok(self);
             }
 
-            bail!("unsupported optional argument type for calling Rust function from JS: {:?}", arg);
+            match *arg {
+                Descriptor::Boolean => {
+                    self.cx.expose_is_like_none();
+                    self.js_arguments.push((name.clone(), "boolean".to_string()));
+                    if self.cx.config.debug {
+                        self.cx.expose_assert_bool();
+                        self.prelude(&format!(
+                            "
+                                if (!isLikeNone({0})) {{
+                                    _assertBoolean({0});
+                                }}
+                            ",
+                            name,
+                        ));
+                    }
+                    self.rust_arguments.push(format!("isLikeNone({0}) ? 0xFFFFFF : {0} ? 1 : 0", name));
+                    return Ok(self);
+                },
+                _ => bail!("unsupported optional argument type for calling Rust function from JS: {:?}", arg),
+            };
         }
 
         if let Some(s) = arg.rust_struct() {
@@ -486,7 +505,17 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
                 return Ok(self);
             }
 
-            bail!("unsupported optional return type for calling Rust function from JS: {:?}", ty);
+            match *ty {
+                Descriptor::Boolean => {
+                    self.ret_ty = "boolean".to_string();
+                    self.ret_expr = "
+                        const ret = RET;
+                        return ret === 0xFFFFFF ? undefined : ret !== 0;
+                    ".to_string();
+                    return Ok(self);
+                },
+                _ => bail!("unsupported optional return type for calling Rust function from JS: {:?}", ty),
+            };
         }
 
         if ty.is_ref_anyref() {
diff --git a/crates/cli-support/src/js/rust2js.rs b/crates/cli-support/src/js/rust2js.rs
index eed1d13c..ceab835e 100644
--- a/crates/cli-support/src/js/rust2js.rs
+++ b/crates/cli-support/src/js/rust2js.rs
@@ -173,7 +173,13 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
                 return Ok(());
             }
 
-            bail!("unsupported optional argument type for calling JS function from Rust: {:?}", arg);
+            match *arg {
+                Descriptor::Boolean => {
+                    self.js_arguments.push(format!("{0} === 0xFFFFFF ? undefined : {0} !== 0", abi));
+                    return Ok(())
+                },
+                _ => bail!("unsupported optional argument type for calling JS function from Rust: {:?}", arg),
+            };
         }
 
         if let Some(signed) = arg.get_64() {
@@ -424,7 +430,17 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
                 return Ok(());
             }
 
-            bail!("unsupported optional return type for calling JS function from Rust: {:?}", ty);
+            match *ty {
+                Descriptor::Boolean => {
+                    self.cx.expose_is_like_none();
+                    self.ret_expr = "
+                        const val = JS;
+                        return isLikeNone(val) ? 0xFFFFFF : val ? 1 : 0;
+                    ".to_string();
+                    return Ok(());
+                },
+                _ => bail!("unsupported optional return type for calling JS function from Rust: {:?}", ty),
+            };
         }
         if ty.is_number() {
             self.ret_expr = "return JS;".to_string();
diff --git a/src/convert/impls.rs b/src/convert/impls.rs
index 05468700..31e37467 100644
--- a/src/convert/impls.rs
+++ b/src/convert/impls.rs
@@ -220,6 +220,16 @@ impl FromWasmAbi for bool {
     }
 }
 
+impl OptionIntoWasmAbi for bool {
+    #[inline]
+    fn none() -> u32 { 0xFFFFFFu32 }
+}
+
+impl OptionFromWasmAbi for bool {
+    #[inline]
+    fn is_none(js: &u32) -> bool { *js == 0xFFFFFFu32 }
+}
+
 impl IntoWasmAbi for char {
     type Abi = u32;
 
diff --git a/tests/wasm/optional_numbers.js b/tests/wasm/optional_numbers.js
index 882c6510..5f29efa8 100644
--- a/tests/wasm/optional_numbers.js
+++ b/tests/wasm/optional_numbers.js
@@ -76,6 +76,10 @@ exports.test_works = function() {
   assert.strictEqual(wasm.u64_identity(wasm.u64_one()), BigInt('1'));
   assert.strictEqual(wasm.u64_identity(wasm.u64_max()), BigInt('18446744073709551615'));
   assert.strictEqual(wasm.u64_identity(wasm.u64_min()), BigInt('0'));
+
+  assert.strictEqual(wasm.bool_identity(wasm.bool_none()), undefined);
+  assert.strictEqual(wasm.bool_identity(wasm.bool_false()), false);
+  assert.strictEqual(wasm.bool_identity(wasm.bool_true()), true);
 };
 
 exports.i32_js_identity = function(a) { return a; };
@@ -90,3 +94,4 @@ exports.i16_js_identity = function(a) { return a; };
 exports.u16_js_identity = function(a) { return a; };
 exports.i64_js_identity = function(a) { return a; };
 exports.u64_js_identity = function(a) { return a; };
+exports.bool_js_identity = function(a) { return a; };
diff --git a/tests/wasm/optional_numbers.rs b/tests/wasm/optional_numbers.rs
index 34f187cd..3722c89b 100644
--- a/tests/wasm/optional_numbers.rs
+++ b/tests/wasm/optional_numbers.rs
@@ -15,6 +15,7 @@ extern {
     fn u16_js_identity(a: Option<u16>) -> Option<u16>;
     fn i64_js_identity(a: Option<i64>) -> Option<i64>;
     fn u64_js_identity(a: Option<u64>) -> Option<u64>;
+    fn bool_js_identity(a: Option<bool>) -> Option<bool>;
 
     fn test_works();
 }
@@ -181,6 +182,15 @@ pub fn u64_min() -> Option<u64> { Some(u64::min_value()) }
 #[wasm_bindgen]
 pub fn u64_identity(a: Option<u64>) -> Option<u64> { u64_js_identity(a) }
 
+#[wasm_bindgen]
+pub fn bool_none() -> Option<bool> { None }
+#[wasm_bindgen]
+pub fn bool_false() -> Option<bool> { Some(false) }
+#[wasm_bindgen]
+pub fn bool_true() -> Option<bool> { Some(true) }
+#[wasm_bindgen]
+pub fn bool_identity(a: Option<bool>) -> Option<bool> { bool_js_identity(a) }
+
 #[wasm_bindgen_test]
 fn works() {
     test_works();