diff --git a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/AbstractUnnormalizedKeysDecoder.kt b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/AbstractUnnormalizedKeysDecoder.kt
deleted file mode 100644
index 79f8e02e..00000000
--- a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/AbstractUnnormalizedKeysDecoder.kt
+++ /dev/null
@@ -1,33 +0,0 @@
-package com.sksamuel.hoplite.decoder
-
-import com.sksamuel.hoplite.ConfigResult
-import com.sksamuel.hoplite.DecoderContext
-import com.sksamuel.hoplite.MapNode
-import com.sksamuel.hoplite.Node
-import com.sksamuel.hoplite.transform
-import kotlin.reflect.KType
-
-/**
- * A decoder which decodes based on unnormalized keys.
- *
- * This is useful for decoders that need to know the original key names.
- *
- * It restores the original key names from the node source key.
- */
-abstract class AbstractUnnormalizedKeysDecoder<T> : NullHandlingDecoder<T> {
-  override fun safeDecode(node: Node, type: KType, context: DecoderContext): ConfigResult<T> {
-    val unnormalizedNode = node.transform {
-      val sourceKey = it.sourceKey
-      when (it) {
-        is MapNode -> it.copy(map = it.map.mapKeys { (k, v) ->
-          (v.sourceKey ?: k).removePrefix("$sourceKey.")
-        })
-        else -> it
-      }
-    }
-
-    return safeDecodeUnnormalized(unnormalizedNode, type, context)
-  }
-
-  abstract fun safeDecodeUnnormalized(node: Node, type: KType, context: DecoderContext): ConfigResult<T>
-}
diff --git a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/MapDecoder.kt b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/MapDecoder.kt
index d53264fb..3c0f538f 100644
--- a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/MapDecoder.kt
+++ b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/decoder/MapDecoder.kt
@@ -1,27 +1,28 @@
 package com.sksamuel.hoplite.decoder
 
 import com.sksamuel.hoplite.ArrayNode
-import com.sksamuel.hoplite.fp.invalid
 import com.sksamuel.hoplite.ConfigFailure
 import com.sksamuel.hoplite.ConfigResult
 import com.sksamuel.hoplite.DecoderContext
 import com.sksamuel.hoplite.MapNode
-import com.sksamuel.hoplite.StringNode
 import com.sksamuel.hoplite.Node
+import com.sksamuel.hoplite.StringNode
+import com.sksamuel.hoplite.denormalize
 import com.sksamuel.hoplite.fp.flatMap
+import com.sksamuel.hoplite.fp.invalid
 import com.sksamuel.hoplite.fp.sequence
 import kotlin.reflect.KType
 import kotlin.reflect.full.isSubtypeOf
 import kotlin.reflect.full.starProjectedType
 import kotlin.reflect.full.withNullability
 
-class MapDecoder : AbstractUnnormalizedKeysDecoder<Map<*, *>>() {
+class MapDecoder : NullHandlingDecoder<Map<*, *>> {
 
   override fun supports(type: KType): Boolean =
     type.isSubtypeOf(Map::class.starProjectedType) ||
       type.isSubtypeOf(Map::class.starProjectedType.withNullability(true))
 
-  override fun safeDecodeUnnormalized(node: Node, type: KType, context: DecoderContext): ConfigResult<Map<*, *>> {
+  override fun safeDecode(node: Node, type: KType, context: DecoderContext): ConfigResult<Map<*, *>> {
     require(type.arguments.size == 2)
 
     val kType = type.arguments[0].type!!
@@ -32,7 +33,7 @@ class MapDecoder : AbstractUnnormalizedKeysDecoder<Map<*, *>>() {
                              vdecoder: Decoder<V>,
                              context: DecoderContext): ConfigResult<Map<*, *>> {
 
-      return node.map.entries.map { (k, v) ->
+      return node.denormalize().map.entries.map { (k, v) ->
         kdecoder.decode(StringNode(k, node.pos, node.path, emptyMap()), kType, context).flatMap { kk ->
           vdecoder.decode(v, vType, context).map { vv ->
             context.usedPaths.add(v.path)
diff --git a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/nodes.kt b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/nodes.kt
index b0a24676..1ef86ce2 100644
--- a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/nodes.kt
+++ b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/nodes.kt
@@ -134,6 +134,19 @@ fun Node.transform(transformer: (Node) -> Node): Node = when (val transformed =
   else -> transformed
 }
 
+/**
+ * Denormalizes a node, restoring its original key from the source. This is not recursive -- it only transforms
+ * the given node, not its children.
+ */
+fun <T : Node> T.denormalize(): T {
+  return when (this) {
+    is MapNode -> copy(map = map.mapKeys { (k, v) ->
+      (v.sourceKey ?: k).removePrefix("$sourceKey.")
+    })
+    else -> this
+  } as T
+}
+
 sealed class ContainerNode : Node
 
 data class MapNode(
diff --git a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/parsers/loadProps.kt b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/parsers/loadProps.kt
index f12b8ad3..46701daa 100644
--- a/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/parsers/loadProps.kt
+++ b/hoplite-core/src/main/kotlin/com/sksamuel/hoplite/parsers/loadProps.kt
@@ -74,7 +74,6 @@ private fun <T, K> Iterable<T>.toNode(
         pos = pos,
         path = path,
         value = value?.transform(path, sourceKey) ?: Undefined,
-        sourceKey = this.sourceKey,
       )
     }
     is Array<*> -> ArrayNode(
diff --git a/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/LoadPropsTest.kt b/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/LoadPropsTest.kt
index 6e81f3c5..8fca0c98 100644
--- a/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/LoadPropsTest.kt
+++ b/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/LoadPropsTest.kt
@@ -27,7 +27,7 @@ class LoadPropsTest : FunSpec({
               pos = Pos.SourcePos(source = "source"),
               DotPath("a", "b"),
               value = Undefined,
-              sourceKey = null
+              sourceKey = "a.b"
             ),
             "d" to StringNode("true", pos = Pos.SourcePos(source = "source"), DotPath("a", "d"), sourceKey = "a.d")
           ),
diff --git a/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/PropsParserTest.kt b/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/PropsParserTest.kt
index f402ea65..5275ba0a 100644
--- a/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/PropsParserTest.kt
+++ b/hoplite-core/src/test/kotlin/com/sksamuel/hoplite/PropsParserTest.kt
@@ -32,7 +32,7 @@ class PropsParserTest : StringSpec() {
               ),
               pos = Pos.SourcePos(source = "a.props"),
               DotPath("a"),
-              sourceKey = null
+              sourceKey = "a"
             ),
             "e" to StringNode(value = "5.5", pos = Pos.SourcePos(source = "a.props"), DotPath("e"), sourceKey = "e")
           ),
diff --git a/hoplite-hikaricp/src/main/kotlin/com/sksamuel/hoplite/hikari/HikariDataSourceDecoder.kt b/hoplite-hikaricp/src/main/kotlin/com/sksamuel/hoplite/hikari/HikariDataSourceDecoder.kt
index c65a24ad..4fca95c0 100644
--- a/hoplite-hikaricp/src/main/kotlin/com/sksamuel/hoplite/hikari/HikariDataSourceDecoder.kt
+++ b/hoplite-hikaricp/src/main/kotlin/com/sksamuel/hoplite/hikari/HikariDataSourceDecoder.kt
@@ -6,25 +6,26 @@ import com.sksamuel.hoplite.DecoderContext
 import com.sksamuel.hoplite.MapNode
 import com.sksamuel.hoplite.Node
 import com.sksamuel.hoplite.PrimitiveNode
-import com.sksamuel.hoplite.decoder.AbstractUnnormalizedKeysDecoder
+import com.sksamuel.hoplite.decoder.Decoder
+import com.sksamuel.hoplite.denormalize
 import com.sksamuel.hoplite.fp.invalid
 import com.sksamuel.hoplite.fp.valid
 import com.zaxxer.hikari.HikariConfig
 import com.zaxxer.hikari.HikariDataSource
-import java.util.Properties
+import java.util.*
 import kotlin.reflect.KType
 
-class HikariDataSourceDecoder : AbstractUnnormalizedKeysDecoder<HikariDataSource>() {
+class HikariDataSourceDecoder : Decoder<HikariDataSource> {
 
   override fun supports(type: KType): Boolean = type.classifier == HikariDataSource::class
 
-  override fun safeDecodeUnnormalized(node: Node, type: KType, context: DecoderContext): ConfigResult<HikariDataSource> {
+  override fun decode(node: Node, type: KType, context: DecoderContext): ConfigResult<HikariDataSource> {
 
     val props = Properties()
 
     fun populate(node: Node, prefix: String) {
       when (node) {
-        is MapNode -> node.map.forEach { (k, v) -> populate(v, if (prefix == "") k else "$prefix.$k") }
+        is MapNode -> node.denormalize().map.forEach { (k, v) -> populate(v, if (prefix == "") k else "$prefix.$k") }
         is PrimitiveNode -> props[prefix] = node.value
         else -> {
         }
diff --git a/hoplite-vavr/src/main/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoder.kt b/hoplite-vavr/src/main/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoder.kt
index a04b65d1..6bd9e3a5 100644
--- a/hoplite-vavr/src/main/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoder.kt
+++ b/hoplite-vavr/src/main/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoder.kt
@@ -32,7 +32,7 @@ class MapDecoder : NullHandlingDecoder<Map<*, *>> {
                              kdecoder: Decoder<K>,
                              vdecoder: Decoder<V>,
                              context: DecoderContext): ConfigResult<Map<*, *>> =
-      node.map.entries.map { (k, v) ->
+      node.denormalize().map.entries.map { (k, v) ->
         kdecoder.decode(StringNode(k, node.pos, node.path, emptyMap()), kType, context).flatMap { kk ->
           vdecoder.decode(v, vType, context).map { vv ->
             kk to vv
diff --git a/hoplite-vavr/src/test/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoderTest.kt b/hoplite-vavr/src/test/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoderTest.kt
index 9a1490d2..dff66619 100644
--- a/hoplite-vavr/src/test/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoderTest.kt
+++ b/hoplite-vavr/src/test/kotlin/com/sksamuel/hoplite/decoder/vavr/MapDecoderTest.kt
@@ -12,7 +12,7 @@ class MapDecoderTest : FunSpec({
     data class Test(val map: Map<String, String>)
 
     val config = ConfigLoader().loadConfigOrThrow<Test>("/test_map.yml")
-    config shouldBe Test(linkedHashMap("key1" to "test1", "key2" to "test2"))
+    config shouldBe Test(linkedHashMap("key1" to "test1", "key2" to "test2", "key-3" to "test3", "Key4" to "test4"))
   }
 
 })
diff --git a/hoplite-vavr/src/test/resources/test_map.yml b/hoplite-vavr/src/test/resources/test_map.yml
index 9c56991c..928fd136 100644
--- a/hoplite-vavr/src/test/resources/test_map.yml
+++ b/hoplite-vavr/src/test/resources/test_map.yml
@@ -1,3 +1,5 @@
 map:
   key1: "test1"
   key2: "test2"
+  key-3: "test3"
+  Key4: "test4"
diff --git a/hoplite-yaml/src/test/kotlin/com/sksamuel/hoplite/yaml/DenormalizedMapKeysTest.kt b/hoplite-yaml/src/test/kotlin/com/sksamuel/hoplite/yaml/DenormalizedMapKeysTest.kt
new file mode 100644
index 00000000..077fa410
--- /dev/null
+++ b/hoplite-yaml/src/test/kotlin/com/sksamuel/hoplite/yaml/DenormalizedMapKeysTest.kt
@@ -0,0 +1,52 @@
+package com.sksamuel.hoplite.yaml
+
+import com.sksamuel.hoplite.ConfigLoaderBuilder
+import com.sksamuel.hoplite.addCommandLineSource
+import com.sksamuel.hoplite.addResourceOrFileSource
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
+
+class DenormalizedMapKeysTest : FunSpec({
+  data class Foo(
+    val xVal: String = "x"
+  )
+
+  data class MapContainer(
+    val m: Map<String, Foo> = emptyMap()
+  )
+
+  test("should set denormalized map keys and decode a data class inside a map") {
+    val config = ConfigLoaderBuilder.default()
+      .addResourceOrFileSource("/test_data_class_in_map.yaml")
+      .build()
+      .loadConfigOrThrow<MapContainer>()
+
+    config shouldBe MapContainer(
+      m = mapOf(
+        "DC1" to Foo("10"),
+        "DC2" to Foo("20"),
+      )
+    )
+  }
+
+  test("should set denormalized map keys for CLI arguments") {
+    val config = ConfigLoaderBuilder.default()
+      .addCommandLineSource(
+        arrayOf(
+          "--m.DC1.x-val=10",
+          "--m.DC2.x-val=20",
+        ),
+        prefix = "--",
+        delimiter = "="
+      )
+      .build()
+      .loadConfigOrThrow<MapContainer>()
+
+    config shouldBe MapContainer(
+      m = mapOf(
+        "DC1" to Foo("10"),
+        "DC2" to Foo("20"),
+      )
+    )
+  }
+})
diff --git a/hoplite-yaml/src/test/resources/test_data_class_in_map.yaml b/hoplite-yaml/src/test/resources/test_data_class_in_map.yaml
new file mode 100644
index 00000000..052fd12c
--- /dev/null
+++ b/hoplite-yaml/src/test/resources/test_data_class_in_map.yaml
@@ -0,0 +1,5 @@
+m:
+  DC1:
+    x-val: 10
+  DC2:
+    x-val: 20