diff --git a/quiche/quic/moqt/moqt_framer.cc b/quiche/quic/moqt/moqt_framer.cc
index 78c9e3a..8439ebf 100644
--- a/quiche/quic/moqt/moqt_framer.cc
+++ b/quiche/quic/moqt/moqt_framer.cc
@@ -18,8 +18,10 @@
 #include "quiche/quic/core/quic_data_writer.h"
 #include "quiche/quic/core/quic_time.h"
 #include "quiche/quic/moqt/moqt_messages.h"
+#include "quiche/quic/moqt/moqt_priority.h"
 #include "quiche/quic/platform/api/quic_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
+#include "quiche/common/platform/api/quiche_logging.h"
 #include "quiche/common/quiche_buffer_allocator.h"
 #include "quiche/common/quiche_data_writer.h"
 #include "quiche/common/simple_buffer_allocator.h"
@@ -124,6 +126,20 @@
   return *std::move(buffer);
 }
 
+WireUint8 WireDeliveryOrder(std::optional<MoqtDeliveryOrder> delivery_order) {
+  if (!delivery_order.has_value()) {
+    return WireUint8(0x00);
+  }
+  switch (*delivery_order) {
+    case MoqtDeliveryOrder::kAscending:
+      return WireUint8(0x01);
+    case MoqtDeliveryOrder::kDescending:
+      return WireUint8(0x02);
+  }
+  QUICHE_NOTREACHED();
+  return WireUint8(0xff);
+}
+
 }  // namespace
 
 quiche::QuicheBuffer MoqtFramer::SerializeObjectHeader(
@@ -323,13 +339,14 @@
     return Serialize(WireVarInt62(MoqtMessageType::kSubscribeOk),
                      WireVarInt62(message.subscribe_id),
                      WireVarInt62(message.expires.ToMilliseconds()),
-                     WireUint8(1), WireVarInt62(message.largest_id->group),
+                     WireDeliveryOrder(message.group_order), WireUint8(1),
+                     WireVarInt62(message.largest_id->group),
                      WireVarInt62(message.largest_id->object));
   }
   return Serialize(WireVarInt62(MoqtMessageType::kSubscribeOk),
                    WireVarInt62(message.subscribe_id),
                    WireVarInt62(message.expires.ToMilliseconds()),
-                   WireUint8(0));
+                   WireDeliveryOrder(message.group_order), WireUint8(0));
 }
 
 quiche::QuicheBuffer MoqtFramer::SerializeSubscribeError(
diff --git a/quiche/quic/moqt/moqt_integration_test.cc b/quiche/quic/moqt/moqt_integration_test.cc
index 80710e5..7899087 100644
--- a/quiche/quic/moqt/moqt_integration_test.cc
+++ b/quiche/quic/moqt/moqt_integration_test.cc
@@ -13,6 +13,7 @@
 #include "quiche/quic/moqt/moqt_known_track_publisher.h"
 #include "quiche/quic/moqt/moqt_messages.h"
 #include "quiche/quic/moqt/moqt_outgoing_queue.h"
+#include "quiche/quic/moqt/moqt_priority.h"
 #include "quiche/quic/moqt/moqt_session.h"
 #include "quiche/quic/moqt/test_tools/moqt_simulator_harness.h"
 #include "quiche/quic/moqt/tools/moqt_mock_visitor.h"
diff --git a/quiche/quic/moqt/moqt_messages.h b/quiche/quic/moqt/moqt_messages.h
index 5521e36..584fcf9 100644
--- a/quiche/quic/moqt/moqt_messages.h
+++ b/quiche/quic/moqt/moqt_messages.h
@@ -267,6 +267,7 @@
   uint64_t subscribe_id;
   // The message uses ms, but expires is in us.
   quic::QuicTimeDelta expires = quic::QuicTimeDelta::FromMilliseconds(0);
+  MoqtDeliveryOrder group_order;
   // If ContextExists on the wire is zero, largest_id has no value.
   std::optional<FullSequence> largest_id;
 };
diff --git a/quiche/quic/moqt/moqt_outgoing_queue.h b/quiche/quic/moqt/moqt_outgoing_queue.h
index 42d6425..e3a7d3a 100644
--- a/quiche/quic/moqt/moqt_outgoing_queue.h
+++ b/quiche/quic/moqt/moqt_outgoing_queue.h
@@ -67,6 +67,9 @@
   MoqtPriority GetPublisherPriority() const override {
     return publisher_priority_;
   }
+  MoqtDeliveryOrder GetDeliveryOrder() const override {
+    return delivery_order_;
+  }
 
   bool HasSubscribers() const { return !listeners_.empty(); }
 
@@ -87,6 +90,7 @@
   FullTrackName track_;
   MoqtForwardingPreference forwarding_preference_;
   MoqtPriority publisher_priority_ = 128;
+  MoqtDeliveryOrder delivery_order_ = MoqtDeliveryOrder::kAscending;
   absl::InlinedVector<Group, kMaxQueuedGroups> queue_;
   uint64_t current_group_id_ = -1;
   absl::flat_hash_set<MoqtObjectListener*> listeners_;
diff --git a/quiche/quic/moqt/moqt_parser.cc b/quiche/quic/moqt/moqt_parser.cc
index a5b180d..c5a51d7 100644
--- a/quiche/quic/moqt/moqt_parser.cc
+++ b/quiche/quic/moqt/moqt_parser.cc
@@ -16,6 +16,7 @@
 #include "quiche/quic/core/quic_data_reader.h"
 #include "quiche/quic/core/quic_time.h"
 #include "quiche/quic/moqt/moqt_messages.h"
+#include "quiche/quic/moqt/moqt_priority.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
 namespace moqt {
@@ -481,9 +482,10 @@
 size_t MoqtParser::ProcessSubscribeOk(quic::QuicDataReader& reader) {
   MoqtSubscribeOk subscribe_ok;
   uint64_t milliseconds;
+  uint8_t group_order;
   uint8_t content_exists;
   if (!reader.ReadVarInt62(&subscribe_ok.subscribe_id) ||
-      !reader.ReadVarInt62(&milliseconds) ||
+      !reader.ReadVarInt62(&milliseconds) || !reader.ReadUInt8(&group_order) ||
       !reader.ReadUInt8(&content_exists)) {
     return 0;
   }
@@ -491,7 +493,12 @@
     ParseError("SUBSCRIBE_OK ContentExists has invalid value");
     return 0;
   }
+  if (group_order != 0x01 && group_order != 0x02) {
+    ParseError("Invalid group order value in SUBSCRIBE_OK");
+    return 0;
+  }
   subscribe_ok.expires = quic::QuicTimeDelta::FromMilliseconds(milliseconds);
+  subscribe_ok.group_order = static_cast<MoqtDeliveryOrder>(group_order);
   if (content_exists) {
     subscribe_ok.largest_id = FullSequence();
     if (!reader.ReadVarInt62(&subscribe_ok.largest_id->group) ||
diff --git a/quiche/quic/moqt/moqt_parser_test.cc b/quiche/quic/moqt/moqt_parser_test.cc
index 80dfade..3cf061a 100644
--- a/quiche/quic/moqt/moqt_parser_test.cc
+++ b/quiche/quic/moqt/moqt_parser_test.cc
@@ -1075,6 +1075,17 @@
             "SUBSCRIBE_OK ContentExists has invalid value");
 }
 
+TEST_F(MoqtMessageSpecificTest, SubscribeOkInvalidDeliveryOrder) {
+  MoqtParser parser(kRawQuic, visitor_);
+  SubscribeOkMessage subscribe_ok;
+  subscribe_ok.SetInvalidDeliveryOrder();
+  parser.ProcessData(subscribe_ok.PacketSample(), false);
+  EXPECT_EQ(visitor_.messages_received_, 0);
+  EXPECT_TRUE(visitor_.parsing_error_.has_value());
+  EXPECT_EQ(*visitor_.parsing_error_,
+            "Invalid group order value in SUBSCRIBE_OK");
+}
+
 TEST_F(MoqtMessageSpecificTest, SubscribeDoneInvalidContentExists) {
   MoqtParser parser(kRawQuic, visitor_);
   SubscribeDoneMessage subscribe_done;
diff --git a/quiche/quic/moqt/moqt_priority.h b/quiche/quic/moqt/moqt_priority.h
index f8c8ad9..85449d9 100644
--- a/quiche/quic/moqt/moqt_priority.h
+++ b/quiche/quic/moqt/moqt_priority.h
@@ -19,8 +19,8 @@
 // Indicates the desired order of delivering groups associated with a given
 // track.
 enum class MoqtDeliveryOrder : uint8_t {
-  kAscending,
-  kDescending,
+  kAscending = 0x01,
+  kDescending = 0x02,
 };
 
 // Computes WebTransport send order for an MoQT data stream with the specified
diff --git a/quiche/quic/moqt/moqt_publisher.h b/quiche/quic/moqt/moqt_publisher.h
index 4c66001..778236c 100644
--- a/quiche/quic/moqt/moqt_publisher.h
+++ b/quiche/quic/moqt/moqt_publisher.h
@@ -94,6 +94,9 @@
 
   // Returns the current forwarding priority of the track.
   virtual MoqtPriority GetPublisherPriority() const = 0;
+
+  // Returns the publisher-preferred delivery order for the track.
+  virtual MoqtDeliveryOrder GetDeliveryOrder() const = 0;
 };
 
 // MoqtPublisher is an interface to a publisher that allows it to publish
diff --git a/quiche/quic/moqt/moqt_session.cc b/quiche/quic/moqt/moqt_session.cc
index db716fb..58ff443 100644
--- a/quiche/quic/moqt/moqt_session.cc
+++ b/quiche/quic/moqt/moqt_session.cc
@@ -27,6 +27,7 @@
 #include "quiche/quic/moqt/moqt_framer.h"
 #include "quiche/quic/moqt/moqt_messages.h"
 #include "quiche/quic/moqt/moqt_parser.h"
+#include "quiche/quic/moqt/moqt_priority.h"
 #include "quiche/quic/moqt/moqt_publisher.h"
 #include "quiche/quic/moqt/moqt_subscribe_windows.h"
 #include "quiche/quic/moqt/moqt_track.h"
@@ -610,6 +611,7 @@
   if (PublisherHasData(**track_publisher)) {
     largest_id = (*track_publisher)->GetLargestSequence();
   }
+  MoqtDeliveryOrder delivery_order = (*track_publisher)->GetDeliveryOrder();
 
   auto subscription = std::make_unique<MoqtSession::PublishedSubscription>(
       session_, *std::move(track_publisher), message);
@@ -622,6 +624,7 @@
 
   MoqtSubscribeOk subscribe_ok;
   subscribe_ok.subscribe_id = message.subscribe_id;
+  subscribe_ok.group_order = delivery_order;
   subscribe_ok.largest_id = largest_id;
   SendOrBufferMessage(session_->framer_.SerializeSubscribeOk(subscribe_ok));
 
diff --git a/quiche/quic/moqt/moqt_session_test.cc b/quiche/quic/moqt/moqt_session_test.cc
index 1b5b2e4..9a1bf9c 100644
--- a/quiche/quic/moqt/moqt_session_test.cc
+++ b/quiche/quic/moqt/moqt_session_test.cc
@@ -679,6 +679,7 @@
   MoqtSubscribeOk ok = {
       /*subscribe_id=*/1,
       /*expires=*/quic::QuicTimeDelta::FromMilliseconds(0),
+      /*group_order=*/MoqtDeliveryOrder::kAscending,
       /*largest_id=*/std::nullopt,
   };
   StrictMock<webtransport::test::MockStream> mock_control_stream;
@@ -851,6 +852,7 @@
   MoqtSubscribeOk ok = {
       /*subscribe_id=*/1,
       /*expires=*/quic::QuicTimeDelta::FromMilliseconds(0),
+      /*group_order=*/MoqtDeliveryOrder::kAscending,
       /*largest_id=*/std::nullopt,
   };
   StrictMock<webtransport::test::MockStream> mock_control_stream;
diff --git a/quiche/quic/moqt/test_tools/moqt_test_message.h b/quiche/quic/moqt/test_tools/moqt_test_message.h
index c4f4976..44a6405 100644
--- a/quiche/quic/moqt/test_tools/moqt_test_message.h
+++ b/quiche/quic/moqt/test_tools/moqt_test_message.h
@@ -18,6 +18,7 @@
 #include "quiche/quic/core/quic_data_writer.h"
 #include "quiche/quic/core/quic_time.h"
 #include "quiche/quic/moqt/moqt_messages.h"
+#include "quiche/quic/moqt/moqt_priority.h"
 #include "quiche/quic/platform/api/quic_logging.h"
 #include "quiche/common/platform/api/quiche_export.h"
 #include "quiche/common/quiche_endian.h"
@@ -496,6 +497,10 @@
       QUIC_LOG(INFO) << "SUBSCRIBE OK expiration mismatch";
       return false;
     }
+    if (cast.group_order != subscribe_ok_.group_order) {
+      QUIC_LOG(INFO) << "SUBSCRIBE OK group order mismatch";
+      return false;
+    }
     if (cast.largest_id != subscribe_ok_.largest_id) {
       QUIC_LOG(INFO) << "SUBSCRIBE OK largest ID mismatch";
       return false;
@@ -503,26 +508,33 @@
     return true;
   }
 
-  void ExpandVarints() override { ExpandVarintsImpl("vvv-vv"); }
+  void ExpandVarints() override { ExpandVarintsImpl("vvv--vv"); }
 
   MessageStructuredData structured_data() const override {
     return TestMessageBase::MessageStructuredData(subscribe_ok_);
   }
 
   void SetInvalidContentExists() {
-    raw_packet_[3] = 0x02;
+    raw_packet_[4] = 0x02;
+    SetWireImage(raw_packet_, sizeof(raw_packet_));
+  }
+
+  void SetInvalidDeliveryOrder() {
+    raw_packet_[3] = 0x10;
     SetWireImage(raw_packet_, sizeof(raw_packet_));
   }
 
  private:
-  uint8_t raw_packet_[6] = {
+  uint8_t raw_packet_[7] = {
       0x04, 0x01, 0x03,  // subscribe_id = 1, expires = 3
+      0x02,              // delivery_order = 2,
       0x01, 0x0c, 0x14,  // largest_group_id = 12, largest_object_id = 20,
   };
 
   MoqtSubscribeOk subscribe_ok_ = {
       /*subscribe_id=*/1,
       /*expires=*/quic::QuicTimeDelta::FromMilliseconds(3),
+      /*group_order=*/MoqtDeliveryOrder::kDescending,
       /*largest_id=*/FullSequence(12, 20),
   };
 };
diff --git a/quiche/quic/moqt/tools/moqt_mock_visitor.h b/quiche/quic/moqt/tools/moqt_mock_visitor.h
index 5ab728a..a5475a3 100644
--- a/quiche/quic/moqt/tools/moqt_mock_visitor.h
+++ b/quiche/quic/moqt/tools/moqt_mock_visitor.h
@@ -45,7 +45,10 @@
 class MockTrackPublisher : public MoqtTrackPublisher {
  public:
   explicit MockTrackPublisher(FullTrackName name)
-      : track_name_(std::move(name)) {}
+      : track_name_(std::move(name)) {
+    ON_CALL(*this, GetDeliveryOrder())
+        .WillByDefault(testing::Return(MoqtDeliveryOrder::kAscending));
+  }
   const FullTrackName& GetTrackName() const override { return track_name_; }
 
   MOCK_METHOD(std::optional<PublishedObject>, GetCachedObject,
@@ -62,6 +65,7 @@
   MOCK_METHOD(MoqtForwardingPreference, GetForwardingPreference, (),
               (const, override));
   MOCK_METHOD(MoqtPriority, GetPublisherPriority, (), (const, override));
+  MOCK_METHOD(MoqtDeliveryOrder, GetDeliveryOrder, (), (const, override));
 
  private:
   FullTrackName track_name_;