diff --git a/modules/core/04-channel/keeper/packet.go b/modules/core/04-channel/keeper/packet.go
index ee73ce54d5f..5832eba7c80 100644
--- a/modules/core/04-channel/keeper/packet.go
+++ b/modules/core/04-channel/keeper/packet.go
@@ -118,8 +118,8 @@ func (k Keeper) RecvPacket(
 		return errorsmod.Wrap(types.ErrChannelNotFound, packet.GetDestChannel())
 	}
 
-	if !slices.Contains([]types.State{types.OPEN, types.FLUSHING}, channel.State) {
-		return errorsmod.Wrapf(types.ErrInvalidChannelState, "expected channel state to be one of [%s, %s], but got %s", types.OPEN, types.FLUSHING, channel.State)
+	if !slices.Contains([]types.State{types.OPEN, types.FLUSHING, types.FLUSHCOMPLETE}, channel.State) {
+		return errorsmod.Wrapf(types.ErrInvalidChannelState, "expected channel state to be one of [%s, %s, %s], but got %s", types.OPEN, types.FLUSHING, types.FLUSHCOMPLETE, channel.State)
 	}
 
 	// If counterpartyUpgrade is stored we need to ensure that the
@@ -300,11 +300,8 @@ func (k Keeper) WriteAcknowledgement(
 		return errorsmod.Wrap(types.ErrChannelNotFound, packet.GetDestChannel())
 	}
 
-	if !channel.IsOpen() {
-		return errorsmod.Wrapf(
-			types.ErrInvalidChannelState,
-			"channel state is not OPEN (got %s)", channel.State.String(),
-		)
+	if !slices.Contains([]types.State{types.OPEN, types.FLUSHING, types.FLUSHCOMPLETE}, channel.State) {
+		return errorsmod.Wrapf(types.ErrInvalidChannelState, "expected one of [%s, %s, %s], got %s", types.OPEN, types.FLUSHING, types.FLUSHCOMPLETE, channel.State)
 	}
 
 	// Authenticate capability to ensure caller has authority to receive packet on this channel
diff --git a/modules/core/04-channel/keeper/packet_test.go b/modules/core/04-channel/keeper/packet_test.go
index 9fc510c0900..1af25835f24 100644
--- a/modules/core/04-channel/keeper/packet_test.go
+++ b/modules/core/04-channel/keeper/packet_test.go
@@ -323,6 +323,38 @@ func (suite *KeeperTestSuite) TestRecvPacket() {
 			},
 			nil,
 		},
+		{
+			"success UNORDERED channel in FLUSHING",
+			func() {
+				// setup uses an UNORDERED channel
+				suite.coordinator.Setup(path)
+				channel := path.EndpointB.GetChannel()
+				channel.State = types.FLUSHING
+				path.EndpointB.SetChannel(channel)
+
+				sequence, err := path.EndpointA.SendPacket(defaultTimeoutHeight, disabledTimeoutTimestamp, ibctesting.MockPacketData)
+				suite.Require().NoError(err)
+				packet = types.NewPacket(ibctesting.MockPacketData, sequence, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, defaultTimeoutHeight, disabledTimeoutTimestamp)
+				channelCap = suite.chainB.GetChannelCapability(path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID)
+			},
+			nil,
+		},
+		{
+			"success UNORDERED channel in FLUSHCOMPLETE",
+			func() {
+				// setup uses an UNORDERED channel
+				suite.coordinator.Setup(path)
+				channel := path.EndpointB.GetChannel()
+				channel.State = types.FLUSHCOMPLETE
+				path.EndpointB.SetChannel(channel)
+
+				sequence, err := path.EndpointA.SendPacket(defaultTimeoutHeight, disabledTimeoutTimestamp, ibctesting.MockPacketData)
+				suite.Require().NoError(err)
+				packet = types.NewPacket(ibctesting.MockPacketData, sequence, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, defaultTimeoutHeight, disabledTimeoutTimestamp)
+				channelCap = suite.chainB.GetChannelCapability(path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID)
+			},
+			nil,
+		},
 		{
 			"success with out of order packet: UNORDERED channel",
 			func() {
@@ -395,21 +427,6 @@ func (suite *KeeperTestSuite) TestRecvPacket() {
 			},
 			types.ErrInvalidPacket,
 		},
-		{
-			"failure while upgrading channel, channel in flush complete state",
-			func() {
-				suite.coordinator.Setup(path)
-				sequence, err := path.EndpointA.SendPacket(defaultTimeoutHeight, disabledTimeoutTimestamp, ibctesting.MockPacketData)
-				suite.Require().NoError(err)
-				packet = types.NewPacket(ibctesting.MockPacketData, sequence, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, defaultTimeoutHeight, disabledTimeoutTimestamp)
-				channelCap = suite.chainB.GetChannelCapability(path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID)
-
-				channel := path.EndpointB.GetChannel()
-				channel.State = types.FLUSHCOMPLETE
-				path.EndpointB.SetChannel(channel)
-			},
-			types.ErrInvalidChannelState,
-		},
 		{
 			"packet already relayed ORDERED channel (no-op)",
 			func() {
@@ -702,6 +719,32 @@ func (suite *KeeperTestSuite) TestWriteAcknowledgement() {
 			},
 			true,
 		},
+		{
+			"success: channel flushing",
+			func() {
+				suite.coordinator.Setup(path)
+				packet = types.NewPacket(ibctesting.MockPacketData, 1, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, defaultTimeoutHeight, disabledTimeoutTimestamp)
+				ack = ibcmock.MockAcknowledgement
+
+				err := path.EndpointB.SetChannelState(types.FLUSHING)
+				suite.Require().NoError(err)
+				channelCap = suite.chainB.GetChannelCapability(path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID)
+			},
+			true,
+		},
+		{
+			"success: channel flush complete",
+			func() {
+				suite.coordinator.Setup(path)
+				packet = types.NewPacket(ibctesting.MockPacketData, 1, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, defaultTimeoutHeight, disabledTimeoutTimestamp)
+				ack = ibcmock.MockAcknowledgement
+
+				err := path.EndpointB.SetChannelState(types.FLUSHCOMPLETE)
+				suite.Require().NoError(err)
+				channelCap = suite.chainB.GetChannelCapability(path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID)
+			},
+			true,
+		},
 		{"channel not found", func() {
 			// use wrong channel naming
 			suite.coordinator.Setup(path)