diff --git a/lib/temporal/connection/converter/payload/proto_json.rb b/lib/temporal/connection/converter/payload/proto_json.rb
index cdbc36f9..dda3a5f2 100644
--- a/lib/temporal/connection/converter/payload/proto_json.rb
+++ b/lib/temporal/connection/converter/payload/proto_json.rb
@@ -15,7 +15,7 @@ def from_payload(payload)
             # TODO: Add error handling.
             message_type = payload.metadata['messageType']
             descriptor = Google::Protobuf::DescriptorPool.generated_pool.lookup(message_type)
-            descriptor.msgclass.decode_json(payload.data)
+            descriptor.msgclass.decode_json(payload.data, ignore_unknown_fields: true)
           end
 
           def to_payload(data)
diff --git a/spec/unit/lib/temporal/connection/converter/payload/proto_json_spec.rb b/spec/unit/lib/temporal/connection/converter/payload/proto_json_spec.rb
index 589c921f..ac293670 100644
--- a/spec/unit/lib/temporal/connection/converter/payload/proto_json_spec.rb
+++ b/spec/unit/lib/temporal/connection/converter/payload/proto_json_spec.rb
@@ -29,4 +29,18 @@
 
     expect(subject.to_payload(input)).to be nil
   end
+
+  describe ".from_payload" do
+    it "ignores unknown fields" do
+      payload = Temporalio::Api::Common::V1::Payload.new(
+        metadata: {
+          'encoding' => described_class::ENCODING,
+          'messageType' => Temporalio::Api::Common::V1::Payload.descriptor.name,
+        },
+        data: { 'unknown' => 'field' }.to_json.b,
+      )
+
+      expect(subject.from_payload(payload)).to be_instance_of(Temporalio::Api::Common::V1::Payload)
+    end
+  end
 end