diff --git a/cm/option.go b/cm/option.go
index cf7024aa..041cdbe4 100644
--- a/cm/option.go
+++ b/cm/option.go
@@ -1,5 +1,7 @@
 package cm
 
+import "encoding/json"
+
 // Option represents a Component Model [option<T>] type.
 //
 // [option<T>]: https://component-model.bytecodealliance.org/design/wit.html#options
@@ -57,3 +59,41 @@ func (o option[T]) Value() T {
 	}
 	return o.some
 }
+
+// MarshalJSON implements the json.Marshaler interface for the public option type.
+func (o Option[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(o.Some())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for the public option type.
+func (o *Option[T]) UnmarshalJSON(data []byte) error {
+	if string(data) == "null" {
+		*o = None[T]()
+		return nil
+	}
+	var v T
+	if err := json.Unmarshal(data, &v); err != nil {
+		return err
+	}
+	*o = Some(v)
+	return nil
+}
+
+// MarshalJSON implements the json.Marshaler interface for the internal option type.
+func (o option[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(o.Some())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for the internal option type.
+func (o *option[T]) UnmarshalJSON(data []byte) error {
+	if string(data) == "null" {
+		o = &option[T]{isSome: false}
+		return nil
+	}
+	var v T
+	if err := json.Unmarshal(data, &v); err != nil {
+		return err
+	}
+	o = &option[T]{isSome: true, some: v}
+	return nil
+}
diff --git a/cm/option_test.go b/cm/option_test.go
index 1b21669c..354178a0 100644
--- a/cm/option_test.go
+++ b/cm/option_test.go
@@ -1,6 +1,9 @@
 package cm
 
-import "testing"
+import (
+	"encoding/json"
+	"testing"
+)
 
 func TestOption(t *testing.T) {
 	o1 := None[string]()
@@ -65,3 +68,116 @@ func TestOption(t *testing.T) {
 		t.Errorf("Value: %v, expected %v", got, want)
 	}
 }
+
+func TestOptionMarshalJSON(t *testing.T) {
+	type TestStruct struct {
+		Field Option[string] `json:"field"`
+	}
+
+	// Test marshaling None
+	ts1 := TestStruct{Field: None[string]()}
+	data1, err := json.Marshal(ts1)
+	if err != nil {
+		t.Fatalf("json.Marshal failed: %v", err)
+	}
+	expected1 := `{"field":null}`
+	if string(data1) != expected1 {
+		t.Errorf("json.Marshal: got %s, expected %s", data1, expected1)
+	}
+
+	// Test marshaling Some
+	ts2 := TestStruct{Field: Some("hello")}
+	data2, err := json.Marshal(ts2)
+	if err != nil {
+		t.Fatalf("json.Marshal failed: %v", err)
+	}
+	expected2 := `{"field":"hello"}`
+	if string(data2) != expected2 {
+		t.Errorf("json.Marshal: got %s, expected %s", data2, expected2)
+	}
+
+	// Test marshaling custom option type
+	type OptionalI32 Option[int32]
+	ts3 := OptionalI32(Some(int32(42)))
+	data3, err := json.Marshal(ts3)
+	if err != nil {
+		t.Fatalf("json.Marshal failed: %v", err)
+	}
+	expected3 := `42`
+	if string(data3) != expected3 {
+		t.Errorf("json.Marshal: got %s, expected %s", data3, expected3)
+	}
+
+	// Test marshaling nested option type
+	type NestedStruct struct {
+		Field Option[Option[int32]] `json:"field"`
+	}
+	ts4 := NestedStruct{Field: Some(Some(int32(42)))}
+	data4, err := json.Marshal(ts4)
+	if err != nil {
+		t.Fatalf("json.Marshal failed: %v", err)
+	}
+	expected4 := `{"field":42}`
+	if string(data4) != expected4 {
+		t.Errorf("json.Marshal: got %s, expected %s", data4, expected4)
+	}
+}
+
+func TestOptionUnmarshalJSON(t *testing.T) {
+	type TestStruct struct {
+		Field Option[string] `json:"field"`
+	}
+
+	// Test unmarshaling None
+	data1 := []byte(`{"field":null}`)
+	var ts1 TestStruct
+	if err := json.Unmarshal(data1, &ts1); err != nil {
+		t.Fatalf("json.Unmarshal failed: %v", err)
+	}
+	if got, want := ts1.Field.None(), true; got != want {
+		t.Errorf("ts1.Field.None: %t, expected %t", got, want)
+	}
+
+	// Test unmarshaling None (not present)
+	data2 := []byte(`{}`)
+	var ts2 TestStruct
+	if err := json.Unmarshal(data2, &ts2); err != nil {
+		t.Fatalf("json.Unmarshal failed: %v", err)
+	}
+	if got, want := ts2.Field.None(), true; got != want {
+		t.Errorf("ts1.Field.None: %t, expected %t", got, want)
+	}
+
+	// Test unmarshaling Some
+	data3 := []byte(`{"field":"hello"}`)
+	var ts3 TestStruct
+	if err := json.Unmarshal(data3, &ts3); err != nil {
+		t.Fatalf("json.Unmarshal failed: %v", err)
+	}
+	if got, want := ts3.Field.isSome, true; got != want {
+		t.Errorf("ts2.Field.Some: %t, expected %t", got, want)
+	}
+	if got, want := ts3.Field.Value(), "hello"; got != want {
+		t.Errorf("ts2.Field.Value: %v, expected %v", got, want)
+	}
+
+	// Test unmarshaling nested option type
+	type NestedStruct struct {
+		Field Option[Option[int32]] `json:"field"`
+	}
+	data5 := []byte(`{"field":42}`)
+	var ns NestedStruct
+	if err := json.Unmarshal(data5, &ns); err != nil {
+		t.Fatalf("json.Unmarshal failed: %v", err)
+	}
+	if got, want := ns.Field.isSome, true; got != want {
+		t.Errorf("ns.Field.Some: %t, expected %t", got, want)
+	}
+	if got, want := ns.Field.Value(), Some(int32(42)); got != want {
+		t.Errorf("ns.Field.Value: %v, expected %v", got, want)
+	}
+	// Deref the inner option to get the value
+	if got, want := ns.Field.Value().Value(), int32(42); got != want {
+		t.Errorf("ns.Field.Value.Value: %v, expected %v", got, want)
+	}
+}