diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5506ddc1cd6..64e4b71993a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -65,6 +65,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (core/02-client, core/03-connection, apps/27-interchain-accounts) [\#6256](https://github.com/cosmos/ibc-go/pull/6256) Add length checking of array fields in messages.
 * (apps/27-interchain-accounts, apps/tranfer, apps/29-fee) [\#6253](https://github.com/cosmos/ibc-go/pull/6253) Allow channel handshake to succeed if fee middleware is wired up on one side, but not the other.
 * (apps/transfer) [\#6268](https://github.com/cosmos/ibc-go/pull/6268) Use memo strings instead of JSON keys in `AllowedPacketData` of transfer authorization.
+* (core/ante) [\#6278](https://github.com/cosmos/ibc-go/pull/6278) Performance: Exclude pruning from tendermint client updates in ante handler executions.
 
 ### Features
 
diff --git a/modules/light-clients/07-tendermint/update.go b/modules/light-clients/07-tendermint/update.go
index 1a88eee5859..9a710f9e686 100644
--- a/modules/light-clients/07-tendermint/update.go
+++ b/modules/light-clients/07-tendermint/update.go
@@ -139,7 +139,11 @@ func (cs ClientState) UpdateState(ctx sdk.Context, cdc codec.BinaryCodec, client
 		return []exported.Height{}
 	}
 
-	cs.pruneOldestConsensusState(ctx, cdc, clientStore)
+	// performance: do not prune in checkTx
+	// simulation must prune for accurate gas estimation
+	if (!ctx.IsCheckTx() && !ctx.IsReCheckTx()) || ctx.ExecMode() == sdk.ExecModeSimulate {
+		cs.pruneOldestConsensusState(ctx, cdc, clientStore)
+	}
 
 	// check for duplicate update
 	if _, found := GetConsensusState(clientStore, cdc, header.GetHeight()); found {
diff --git a/modules/light-clients/07-tendermint/update_test.go b/modules/light-clients/07-tendermint/update_test.go
index 93ef5638e7e..178ffa6195b 100644
--- a/modules/light-clients/07-tendermint/update_test.go
+++ b/modules/light-clients/07-tendermint/update_test.go
@@ -5,6 +5,8 @@ import (
 
 	storetypes "cosmossdk.io/store/types"
 
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
 	cmttypes "github.com/cometbft/cometbft/types"
 
 	clienttypes "github.com/cosmos/ibc-go/v8/modules/core/02-client/types"
@@ -560,6 +562,78 @@ func (suite *TendermintTestSuite) TestUpdateState() {
 	}
 }
 
+func (suite *TendermintTestSuite) TestUpdateStateCheckTx() {
+	path := ibctesting.NewPath(suite.chainA, suite.chainB)
+	path.SetupClients()
+
+	createClientMessage := func() exported.ClientMessage {
+		trustedHeight, ok := path.EndpointA.GetClientLatestHeight().(clienttypes.Height)
+		suite.Require().True(ok)
+		header, err := path.EndpointB.Chain.IBCClientHeader(path.EndpointB.Chain.LatestCommittedHeader, trustedHeight)
+		suite.Require().NoError(err)
+		return header
+	}
+
+	// get the first height as it will be pruned first.
+	var pruneHeight exported.Height
+	getFirstHeightCb := func(height exported.Height) bool {
+		pruneHeight = height
+		return true
+	}
+	ctx := path.EndpointA.Chain.GetContext()
+	clientStore := path.EndpointA.Chain.App.GetIBCKeeper().ClientKeeper.ClientStore(ctx, path.EndpointA.ClientID)
+	ibctm.IterateConsensusStateAscending(clientStore, getFirstHeightCb)
+
+	// Increment the time by a week
+	suite.coordinator.IncrementTimeBy(7 * 24 * time.Hour)
+
+	lightClientModule, found := suite.chainA.App.GetIBCKeeper().ClientKeeper.Route(path.EndpointA.ClientID)
+	suite.Require().True(found)
+
+	ctx = path.EndpointA.Chain.GetContext().WithIsCheckTx(true)
+	lightClientModule.UpdateState(ctx, path.EndpointA.ClientID, createClientMessage())
+
+	// Increment the time by another week, then update the client.
+	// This will cause the first two consensus states to become expired.
+	suite.coordinator.IncrementTimeBy(7 * 24 * time.Hour)
+	ctx = path.EndpointA.Chain.GetContext().WithIsCheckTx(true)
+	lightClientModule.UpdateState(ctx, path.EndpointA.ClientID, createClientMessage())
+
+	assertPrune := func(pruned bool) {
+		// check consensus states and associated metadata
+		consState, ok := path.EndpointA.Chain.GetConsensusState(path.EndpointA.ClientID, pruneHeight)
+		suite.Require().Equal(!pruned, ok)
+
+		processTime, ok := ibctm.GetProcessedTime(clientStore, pruneHeight)
+		suite.Require().Equal(!pruned, ok)
+
+		processHeight, ok := ibctm.GetProcessedHeight(clientStore, pruneHeight)
+		suite.Require().Equal(!pruned, ok)
+
+		consKey := ibctm.GetIterationKey(clientStore, pruneHeight)
+
+		if pruned {
+			suite.Require().Nil(consState, "expired consensus state not pruned")
+			suite.Require().Empty(processTime, "processed time metadata not pruned")
+			suite.Require().Nil(processHeight, "processed height metadata not pruned")
+			suite.Require().Nil(consKey, "iteration key not pruned")
+		} else {
+			suite.Require().NotNil(consState, "expired consensus state pruned")
+			suite.Require().NotEqual(uint64(0), processTime, "processed time metadata pruned")
+			suite.Require().NotNil(processHeight, "processed height metadata pruned")
+			suite.Require().NotNil(consKey, "iteration key pruned")
+		}
+	}
+
+	assertPrune(false)
+
+	// simulation mode must prune to calculate gas correctly
+	ctx = ctx.WithExecMode(sdk.ExecModeSimulate)
+	lightClientModule.UpdateState(ctx, path.EndpointA.ClientID, createClientMessage())
+
+	assertPrune(true)
+}
+
 func (suite *TendermintTestSuite) TestPruneConsensusState() {
 	// create path and setup clients
 	path := ibctesting.NewPath(suite.chainA, suite.chainB)