diff --git a/quic/core/quic_config.cc b/quic/core/quic_config.cc
index ef4fdad..cad98db 100644
--- a/quic/core/quic_config.cc
+++ b/quic/core/quic_config.cc
@@ -562,7 +562,7 @@
     uint32_t window_bytes) {
   if (window_bytes < kMinimumFlowControlSendWindow) {
     QUIC_BUG << "Initial stream flow control receive window (" << window_bytes
-             << ") cannot be set lower than default ("
+             << ") cannot be set lower than minimum ("
              << kMinimumFlowControlSendWindow << ").";
     window_bytes = kMinimumFlowControlSendWindow;
   }
diff --git a/quic/core/quic_constants.h b/quic/core/quic_constants.h
index a18c07b..81bed70 100644
--- a/quic/core/quic_constants.h
+++ b/quic/core/quic_constants.h
@@ -61,7 +61,10 @@
 const QuicPacketCount kMaxInitialCongestionWindow = 200;
 
 // Minimum size of initial flow control window, for both stream and session.
+// This is only enforced when version.AllowsLowFlowControlLimits() is false.
 const uint32_t kMinimumFlowControlSendWindow = 16 * 1024;  // 16 KB
+// Default size of initial flow control window, for both stream and session.
+const uint32_t kDefaultFlowControlSendWindow = 16 * 1024;  // 16 KB
 
 // Maximum flow control receive window limits for connection and stream.
 const QuicByteCount kStreamReceiveWindowLimit = 16 * 1024 * 1024;   // 16 MB
diff --git a/quic/core/quic_session.cc b/quic/core/quic_session.cc
index 2b9ffa5..5d02a12 100644
--- a/quic/core/quic_session.cc
+++ b/quic/core/quic_session.cc
@@ -69,7 +69,9 @@
           this,
           QuicUtils::GetInvalidStreamId(connection->transport_version()),
           /*is_connection_flow_controller*/ true,
-          kMinimumFlowControlSendWindow,
+          connection->version().AllowsLowFlowControlLimits()
+              ? 0
+              : kMinimumFlowControlSendWindow,
           config_.GetInitialSessionFlowControlWindowToSend(),
           kSessionReceiveWindowLimit,
           perspective() == Perspective::IS_SERVER,
@@ -1054,10 +1056,11 @@
 }
 
 void QuicSession::OnNewStreamFlowControlWindow(QuicStreamOffset new_window) {
-  if (new_window < kMinimumFlowControlSendWindow) {
+  if (new_window < kMinimumFlowControlSendWindow &&
+      !connection_->version().AllowsLowFlowControlLimits()) {
     QUIC_LOG_FIRST_N(ERROR, 1)
         << "Peer sent us an invalid stream flow control send window: "
-        << new_window << ", below default: " << kMinimumFlowControlSendWindow;
+        << new_window << ", below minimum: " << kMinimumFlowControlSendWindow;
     if (connection_->connected()) {
       connection_->CloseConnection(
           QUIC_FLOW_CONTROL_INVALID_WINDOW, "New stream window too low",
@@ -1080,7 +1083,8 @@
 }
 
 void QuicSession::OnNewSessionFlowControlWindow(QuicStreamOffset new_window) {
-  if (new_window < kMinimumFlowControlSendWindow) {
+  if (new_window < kMinimumFlowControlSendWindow &&
+      !connection_->version().AllowsLowFlowControlLimits()) {
     QUIC_LOG_FIRST_N(ERROR, 1)
         << "Peer sent us an invalid session flow control send window: "
         << new_window << ", below default: " << kMinimumFlowControlSendWindow;
diff --git a/quic/core/quic_session_test.cc b/quic/core/quic_session_test.cc
index dddde7d..ad6d324 100644
--- a/quic/core/quic_session_test.cc
+++ b/quic/core/quic_session_test.cc
@@ -1448,8 +1448,12 @@
   QuicConfigPeer::SetReceivedInitialStreamFlowControlWindow(session_.config(),
                                                             kInvalidWindow);
 
-  EXPECT_CALL(*connection_,
-              CloseConnection(QUIC_FLOW_CONTROL_INVALID_WINDOW, _, _));
+  if (!connection_->version().AllowsLowFlowControlLimits()) {
+    EXPECT_CALL(*connection_,
+                CloseConnection(QUIC_FLOW_CONTROL_INVALID_WINDOW, _, _));
+  } else {
+    EXPECT_CALL(*connection_, CloseConnection(_, _, _)).Times(0);
+  }
   session_.OnConfigNegotiated();
 }
 
@@ -1459,9 +1463,12 @@
   const uint32_t kInvalidWindow = kMinimumFlowControlSendWindow - 1;
   QuicConfigPeer::SetReceivedInitialSessionFlowControlWindow(session_.config(),
                                                              kInvalidWindow);
-
-  EXPECT_CALL(*connection_,
-              CloseConnection(QUIC_FLOW_CONTROL_INVALID_WINDOW, _, _));
+  if (!connection_->version().AllowsLowFlowControlLimits()) {
+    EXPECT_CALL(*connection_,
+                CloseConnection(QUIC_FLOW_CONTROL_INVALID_WINDOW, _, _));
+  } else {
+    EXPECT_CALL(*connection_, CloseConnection(_, _, _)).Times(0);
+  }
   session_.OnConfigNegotiated();
 }
 
diff --git a/quic/core/quic_stream.cc b/quic/core/quic_stream.cc
index 4fba898..f9b19b1 100644
--- a/quic/core/quic_stream.cc
+++ b/quic/core/quic_stream.cc
@@ -33,7 +33,7 @@
     return session->config()->ReceivedInitialStreamFlowControlWindowBytes();
   }
 
-  return kMinimumFlowControlSendWindow;
+  return kDefaultFlowControlSendWindow;
 }
 
 }  // namespace
diff --git a/quic/core/quic_versions.cc b/quic/core/quic_versions.cc
index a37f3a7..92232ba 100644
--- a/quic/core/quic_versions.cc
+++ b/quic/core/quic_versions.cc
@@ -42,6 +42,11 @@
          handshake_protocol == PROTOCOL_TLS1_3;
 }
 
+bool ParsedQuicVersion::AllowsLowFlowControlLimits() const {
+  return transport_version == QUIC_VERSION_99 &&
+         handshake_protocol == PROTOCOL_TLS1_3;
+}
+
 std::ostream& operator<<(std::ostream& os, const ParsedQuicVersion& version) {
   os << ParsedQuicVersionToString(version);
   return os;
diff --git a/quic/core/quic_versions.h b/quic/core/quic_versions.h
index 160adeb..8da7361 100644
--- a/quic/core/quic_versions.h
+++ b/quic/core/quic_versions.h
@@ -147,6 +147,10 @@
   }
 
   bool KnowsWhichDecrypterToUse() const;
+
+  // Indicates that this QUIC version does not have an enforced minimum value
+  // for flow control values negotiated during the handshake.
+  bool AllowsLowFlowControlLimits() const;
 };
 
 QUIC_EXPORT_PRIVATE ParsedQuicVersion UnsupportedQuicVersion();
diff --git a/quic/tools/quic_client_base.cc b/quic/tools/quic_client_base.cc
index db0503c..57cbd9a 100644
--- a/quic/tools/quic_client_base.cc
+++ b/quic/tools/quic_client_base.cc
@@ -54,11 +54,11 @@
   const uint32_t kSessionMaxRecvWindowSize = 15 * 1024 * 1024;  // 15 MB
   const uint32_t kStreamMaxRecvWindowSize = 6 * 1024 * 1024;    //  6 MB
   if (config()->GetInitialStreamFlowControlWindowToSend() ==
-      kMinimumFlowControlSendWindow) {
+      kDefaultFlowControlSendWindow) {
     config()->SetInitialStreamFlowControlWindowToSend(kStreamMaxRecvWindowSize);
   }
   if (config()->GetInitialSessionFlowControlWindowToSend() ==
-      kMinimumFlowControlSendWindow) {
+      kDefaultFlowControlSendWindow) {
     config()->SetInitialSessionFlowControlWindowToSend(
         kSessionMaxRecvWindowSize);
   }
diff --git a/quic/tools/quic_server.cc b/quic/tools/quic_server.cc
index d67bc30..f8df59a 100644
--- a/quic/tools/quic_server.cc
+++ b/quic/tools/quic_server.cc
@@ -90,12 +90,12 @@
   const uint32_t kInitialSessionFlowControlWindow = 1 * 1024 * 1024;  // 1 MB
   const uint32_t kInitialStreamFlowControlWindow = 64 * 1024;         // 64 KB
   if (config_.GetInitialStreamFlowControlWindowToSend() ==
-      kMinimumFlowControlSendWindow) {
+      kDefaultFlowControlSendWindow) {
     config_.SetInitialStreamFlowControlWindowToSend(
         kInitialStreamFlowControlWindow);
   }
   if (config_.GetInitialSessionFlowControlWindowToSend() ==
-      kMinimumFlowControlSendWindow) {
+      kDefaultFlowControlSendWindow) {
     config_.SetInitialSessionFlowControlWindowToSend(
         kInitialSessionFlowControlWindow);
   }