diff --git a/modules/core/shared/src/test/scala/neotype/test/definitions/Newtypes.scala b/modules/core/shared/src/test/scala/neotype/test/definitions/Newtypes.scala
index b1c76d3..b2917dc 100644
--- a/modules/core/shared/src/test/scala/neotype/test/definitions/Newtypes.scala
+++ b/modules/core/shared/src/test/scala/neotype/test/definitions/Newtypes.scala
@@ -40,3 +40,12 @@ case class CompositeUnderlying(
     subtype: String,
     simpleSubtype: Int
 )
+
+// Test types for stacked types
+type NewtypeValidatedSubtype = NewtypeValidatedSubtype.Type
+object NewtypeValidatedSubtype extends Newtype[ValidatedSubtype]
+
+type TwiceValidatedSubtype = TwiceValidatedSubtype.Type
+object TwiceValidatedSubtype extends Subtype[ValidatedSubtype]:
+  override inline def validate(input: ValidatedSubtype): Boolean | String =
+    if input.length > 15 then true else "String must be longer than 15 characters"
diff --git a/modules/neotype-zio-config/src/main/scala/neotype/interop/zioconfig/ZioConfigInstances.scala b/modules/neotype-zio-config/src/main/scala/neotype/interop/zioconfig/ZioConfigInstances.scala
index ef25bba..8977ae3 100644
--- a/modules/neotype-zio-config/src/main/scala/neotype/interop/zioconfig/ZioConfigInstances.scala
+++ b/modules/neotype-zio-config/src/main/scala/neotype/interop/zioconfig/ZioConfigInstances.scala
@@ -10,3 +10,24 @@ given validated[A, B](using nt: ValidatedWrappedType[A, B], config: DeriveConfig
 
 given simple[A, B](using nt: SimpleWrappedType[A, B], config: DeriveConfig[A]): DeriveConfig[B] =
   nt.unsafeMakeF(config)
+
+given validatedMap[A, B, V](using
+    nt: ValidatedWrappedType[A, B],
+    mapConfig: DeriveConfig[Map[A, V]]
+): DeriveConfig[Map[B, V]] =
+  mapConfig.mapOrFail(avMap =>
+    avMap.foldLeft[Either[Config.Error, Map[B, V]]](Right(Map.empty)) { case (acc, (keyA, value)) =>
+      for
+        map <- acc
+        b <- nt.make(keyA)
+               .left
+               .map(e => Config.Error.InvalidData(Chunk.empty, message = e))
+      yield map + (b -> value)
+    }
+  )
+
+given simpleMap[A, B, V](using
+    nt: SimpleWrappedType[A, B],
+    mapConfig: DeriveConfig[Map[A, V]]
+): DeriveConfig[Map[B, V]] =
+  mapConfig.map(avMap => avMap.map((a, v) => nt.unsafeMake(a) -> v))
diff --git a/modules/neotype-zio-config/src/test/scala/neotype/interop/zioconfig/ZioConfigSpec.scala b/modules/neotype-zio-config/src/test/scala/neotype/interop/zioconfig/ZioConfigSpec.scala
index e3b02e5..3a60307 100644
--- a/modules/neotype-zio-config/src/test/scala/neotype/interop/zioconfig/ZioConfigSpec.scala
+++ b/modules/neotype-zio-config/src/test/scala/neotype/interop/zioconfig/ZioConfigSpec.scala
@@ -8,6 +8,16 @@ import zio.config.magnolia.*
 import zio.test.*
 
 object ZioConfigSpec extends ZIOSpecDefault:
+  case class ValidatedMapConfig(entries: Map[ValidatedNewtype, Int])
+  case class ValidatedSubtypeMapConfig(entries: Map[ValidatedSubtype, Int])
+  case class NewtypeValidatedSubtypeMapConfig(entries: Map[NewtypeValidatedSubtype, Int])
+  case class TwiceValidatedSubtypeMapConfig(entries: Map[TwiceValidatedSubtype, Int])
+
+  type SimpleStringNewtype = SimpleStringNewtype.Type
+  object SimpleStringNewtype extends Newtype[String]
+
+  case class SimpleMapConfig(entries: Map[SimpleStringNewtype, Int])
+
   def spec = suite("zio-config")(
     test("successfully read config") {
       val expectedConfig = Composite(
@@ -44,5 +54,83 @@ object ZioConfigSpec extends ZIOSpecDefault:
         config.is(_.left).getMessage.contains("String must not be empty"),
         config.is(_.left).getMessage.contains("String must be longer than 10 characters")
       )
-    }
+    },
+    suite("Map")(
+      test("validated map keys") {
+        val expectedConfig = ValidatedMapConfig(
+          Map(ValidatedNewtype("hello") -> 1, ValidatedNewtype("world") -> 2)
+        )
+
+        val source = ConfigProvider.fromMap(
+          Map(
+            "entries.hello" -> "1",
+            "entries.world" -> "2"
+          )
+        )
+
+        for config <- read(deriveConfig[ValidatedMapConfig] from source)
+        yield assertTrue(config == expectedConfig)
+      },
+      test("simple map keys") {
+        val expectedConfig = SimpleMapConfig(
+          Map(SimpleStringNewtype("foo") -> 1, SimpleStringNewtype("bar") -> 2)
+        )
+
+        val source = ConfigProvider.fromMap(
+          Map(
+            "entries.foo" -> "1",
+            "entries.bar" -> "2"
+          )
+        )
+
+        for config <- read(deriveConfig[SimpleMapConfig] from source)
+        yield assertTrue(config == expectedConfig)
+      },
+      test("fails with invalid validated map keys") {
+        val source = ConfigProvider.fromMap(
+          Map(
+            "entries.short" -> "1"
+          )
+        )
+
+        for config <- read(deriveConfig[ValidatedSubtypeMapConfig] from source).either
+        yield assertTrue(
+          config.is(_.left).getMessage.contains("String must be longer than 10 characters")
+        )
+      },
+      test("NewtypeValidatedSubtype map keys") {
+        val expectedConfig = NewtypeValidatedSubtypeMapConfig(
+          Map(NewtypeValidatedSubtype(ValidatedSubtype("long enough key")) -> 1)
+        )
+
+        val source = ConfigProvider.fromMap(
+          Map("entries.long enough key" -> "1")
+        )
+
+        for config <- read(deriveConfig[NewtypeValidatedSubtypeMapConfig] from source)
+        yield assertTrue(config == expectedConfig)
+      },
+      test("TwiceValidatedSubtype map keys") {
+        val expectedConfig = TwiceValidatedSubtypeMapConfig(
+          Map(TwiceValidatedSubtype.makeOrThrow(ValidatedSubtype("this key is long enough")) -> 1)
+        )
+
+        val source = ConfigProvider.fromMap(
+          Map("entries.this key is long enough" -> "1")
+        )
+
+        for config <- read(deriveConfig[TwiceValidatedSubtypeMapConfig] from source)
+        yield assertTrue(config == expectedConfig)
+      },
+      test("fails with TwiceValidatedSubtype map keys that are too short") {
+        val source = ConfigProvider.fromMap(
+          Map("entries.twelve chars" -> "1")
+        )
+
+        for config <- read(deriveConfig[TwiceValidatedSubtypeMapConfig] from source).either
+        yield assertTrue(
+          config.is(_.left).getMessage.contains("String must be longer than 15 characters")
+        )
+      }
+    )
   )