diff --git a/zio-schema-json/shared/src/main/scala/zio/schema/codec/JsonCodec.scala b/zio-schema-json/shared/src/main/scala/zio/schema/codec/JsonCodec.scala
index b72d8af6d..586860b04 100644
--- a/zio-schema-json/shared/src/main/scala/zio/schema/codec/JsonCodec.scala
+++ b/zio-schema-json/shared/src/main/scala/zio/schema/codec/JsonCodec.scala
@@ -991,7 +991,29 @@ object JsonCodec {
     import JsonCodec.JsonDecoder.schemaDecoder
 
     private[codec] def caseClass0Decoder[Z](discriminator: Int, schema: Schema.CaseClass0[Z]): ZJsonDecoder[Z] = { (trace: List[JsonError], in: RetractReader) =>
-      if (discriminator == -1) Codecs.unitDecoder.unsafeDecode(trace, in)
+      def skipField(): Unit = {
+        val rejectExtraFields = schema.annotations.collectFirst({ case _: rejectExtraFields => () }).isDefined
+        if (rejectExtraFields) {
+          throw UnsafeJson(JsonError.Message("extra field") :: trace)
+        }
+        Lexer.char(trace, in, '"')
+        Lexer.skipString(trace, in)
+        Lexer.char(trace, in, ':')
+        Lexer.skipValue(trace, in)
+      }
+
+      if (discriminator == -2) {
+        while (Lexer.nextField(trace, in)) { skipField() }
+      } else {
+        if (discriminator == -1) {
+          Lexer.char(trace, in, '{')
+        }
+        if (Lexer.firstField(trace, in)) {
+          skipField()
+          while (Lexer.nextField(trace, in)) { skipField() }
+        }
+      }
+
       schema.defaultConstruct()
     }
 
diff --git a/zio-schema-json/shared/src/test/scala-2/zio/schema/codec/JsonCodecSpec.scala b/zio-schema-json/shared/src/test/scala-2/zio/schema/codec/JsonCodecSpec.scala
index 115bee8e5..e4957af48 100644
--- a/zio-schema-json/shared/src/test/scala-2/zio/schema/codec/JsonCodecSpec.scala
+++ b/zio-schema-json/shared/src/test/scala-2/zio/schema/codec/JsonCodecSpec.scala
@@ -524,7 +524,12 @@ object JsonCodecSpec extends ZIOSpecDefault {
           PersonWithRejectExtraFields.schema,
           """{"name":"test","age":10,"extraField":10}""",
           JsonError.Message("extra field") :: Nil
-        )
+        ) &>
+          assertDecodesToError(
+            schemaObject.annotate(rejectExtraFields()),
+            """{"extraField":10}""",
+            JsonError.Message("extra field") :: Nil
+          )
       },
       test("transient field annotation") {
         assertDecodes(
@@ -1242,6 +1247,13 @@ object JsonCodecSpec extends ZIOSpecDefault {
         assertEncodesThenDecodes(Schema[Command], Command.Cash) &>
           assertEncodesThenDecodes(Schema[Command], Command.Buy(100))
       },
+      test("decode discriminated case objects in array")(
+        assertDecodes(Schema[List[Command]], Command.Cash :: Nil, charSequenceToByteChunk("""[{"type":"Cash"}]"""))
+      ),
+      test("decode discriminated case objects with extra fields")(
+        assertDecodes(Schema[Command], Command.Cash, charSequenceToByteChunk("""{"type":"Cash","extraField":1}""")) &>
+          assertDecodes(Schema[Command], Command.Cash, charSequenceToByteChunk("""{"extraField":1,"type":"Cash"}""""))
+      ),
       suite("of case objects")(
         test("without annotation")(
           assertEncodesThenDecodes(Schema[Color], Color.Red)
@@ -1593,6 +1605,7 @@ object JsonCodecSpec extends ZIOSpecDefault {
 
     val schema: Schema[PersonWithRejectExtraFields] = DeriveSchema.gen[PersonWithRejectExtraFields]
   }
+
   case class FieldDefaultValueSearchRequest(
     query: String,
     pageNumber: Int,
diff --git a/zio-schema-json/shared/src/test/scala-3/zio/schema/codec/DefaultValueSpec.scala b/zio-schema-json/shared/src/test/scala-3/zio/schema/codec/DefaultValueSpec.scala
index cd65b6a00..4b2dd94bc 100644
--- a/zio-schema-json/shared/src/test/scala-3/zio/schema/codec/DefaultValueSpec.scala
+++ b/zio-schema-json/shared/src/test/scala-3/zio/schema/codec/DefaultValueSpec.scala
@@ -12,7 +12,7 @@ object DefaultValueSpec extends ZIOSpecDefault {
 
   def spec: Spec[TestEnvironment, Any] =
     suite("Custom Spec")(
-      customSuite,
+      customSuite
     ) @@ timeout(90.seconds)
 
   private val customSuite = suite("custom")(
@@ -24,7 +24,7 @@ object DefaultValueSpec extends ZIOSpecDefault {
     )
   )
 
-  case class WithDefaultValue(orderId:Int, description: String = "desc")
+  case class WithDefaultValue(orderId: Int, description: String = "desc")
 
   object WithDefaultValue {
     implicit lazy val schema: Schema[WithDefaultValue] = DeriveSchema.gen[WithDefaultValue]