diff --git a/Sources/Tagged/Tagged.swift b/Sources/Tagged/Tagged.swift
index e3d57aa..cfcfb50 100644
--- a/Sources/Tagged/Tagged.swift
+++ b/Sources/Tagged/Tagged.swift
@@ -89,6 +89,21 @@ extension Tagged: Encodable where RawValue: Encodable {
   }
 }
 
+#if swift(>=5.6)
+  @available(macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4, *)
+  extension Tagged: CodingKeyRepresentable where RawValue: CodingKeyRepresentable {
+    public init?<T: CodingKey>(codingKey: T) {
+      guard let rawValue = RawValue(codingKey: codingKey)
+      else { return nil }
+      self.init(rawValue: rawValue)
+    }
+
+    public var codingKey: CodingKey {
+      self.rawValue.codingKey
+    }
+  }
+#endif
+
 extension Tagged: Equatable where RawValue: Equatable {}
 
 extension Tagged: Error where RawValue: Error {}
diff --git a/Tests/TaggedTests/TaggedTests.swift b/Tests/TaggedTests/TaggedTests.swift
index 0fc1416..a36fa94 100644
--- a/Tests/TaggedTests/TaggedTests.swift
+++ b/Tests/TaggedTests/TaggedTests.swift
@@ -70,6 +70,19 @@ final class TaggedTests: XCTestCase {
     )
   }
 
+  #if swift(>=5.6)
+    func testCodingKeyRepresentable() {
+      if #available(macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4, *) {
+        enum Key {}
+        let xs: [Tagged<Key, String>: String] = [Tagged("Hello"): "World"]
+        XCTAssertEqual(
+          String(decoding: try JSONEncoder().encode(xs), as: UTF8.self),
+          #"{"Hello":"World"}"#
+        )
+      }
+    }
+  #endif
+
   func testEquatable() {
     XCTAssertEqual(Tagged<Tag, Int>(rawValue: 1), Tagged<Tag, Int>(rawValue: 1))
   }