diff --git a/CHANGELOG.md b/CHANGELOG.md
index 67240c92ec9d..4ee3be853fa2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -83,6 +83,7 @@ This patch update also includes minor dependency bumps.
 
 ### Improvements
 
+* [#24207](https://github.com/cosmos/cosmos-sdk/pull/24207) Avoid decoding tx for in PrepareProposal if it's NoOpMempool.
 * (types) [#25342](https://github.com/cosmos/cosmos-sdk/pull/25342) Undeprecated `EmitEvent` and `EmitEvents` on the `EventManager`.  These functions will continue to be maintained.
 * (types) [#24668](https://github.com/cosmos/cosmos-sdk/pull/24668) Scope the global config to a particular binary so that multiple SDK binaries can be properly run on the same machine.
 * (baseapp) [#24655](https://github.com/cosmos/cosmos-sdk/pull/24655) Add mutex locks for `state` and make `lastCommitInfo` atomic to prevent race conditions between `Commit` and `CreateQueryContext`.
diff --git a/baseapp/abci_utils.go b/baseapp/abci_utils.go
index 9c53f0f6550b..6e95f28e5ff4 100644
--- a/baseapp/abci_utils.go
+++ b/baseapp/abci_utils.go
@@ -213,6 +213,9 @@ type (
 		txVerifier       ProposalTxVerifier
 		txSelector       TxSelector
 		signerExtAdapter mempool.SignerExtractionAdapter
+
+		// fastPrepareProposal together with NoOpMempool will bypass tx selector
+		fastPrepareProposal bool
 	}
 )
 
@@ -225,6 +228,12 @@ func NewDefaultProposalHandler(mp mempool.Mempool, txVerifier ProposalTxVerifier
 	}
 }
 
+func NewDefaultProposalHandlerFast(mp mempool.Mempool, txVerifier ProposalTxVerifier) *DefaultProposalHandler {
+	h := NewDefaultProposalHandler(mp, txVerifier)
+	h.fastPrepareProposal = true
+	return h
+}
+
 // SetTxSelector sets the TxSelector function on the DefaultProposalHandler.
 func (h *DefaultProposalHandler) SetTxSelector(ts TxSelector) {
 	h.txSelector = ts
@@ -270,6 +279,11 @@ func (h *DefaultProposalHandler) PrepareProposalHandler() sdk.PrepareProposalHan
 		// Note, we still need to ensure the transactions returned respect req.MaxTxBytes.
 		_, isNoOp := h.mempool.(mempool.NoOpMempool)
 		if h.mempool == nil || isNoOp {
+			if h.fastPrepareProposal {
+				txs := h.txSelector.SelectTxForProposalFast(ctx, req.Txs)
+				return &abci.ResponsePrepareProposal{Txs: txs}, nil
+			}
+
 			for _, txBz := range req.Txs {
 				tx, err := h.txVerifier.TxDecode(txBz)
 				if err != nil {
@@ -478,6 +492,11 @@ type TxSelector interface {
 	// return <true> if the caller should halt the transaction selection loop
 	// (typically over a mempool) or <false> otherwise.
 	SelectTxForProposal(ctx context.Context, maxTxBytes, maxBlockGas uint64, memTx sdk.Tx, txBz []byte) bool
+	// SelectTxForProposalFast is called in the case of NoOpMempool,
+	// where cometbft already checked the block gas/size limit,
+	// so the tx selector should simply accept them all to the proposal.
+	// But extra validations on the tx are still possible though.
+	SelectTxForProposalFast(ctx context.Context, txs [][]byte) [][]byte
 }
 
 type defaultTxSelector struct {
@@ -499,7 +518,7 @@ func (ts *defaultTxSelector) SelectedTxs(_ context.Context) [][]byte {
 func (ts *defaultTxSelector) Clear() {
 	ts.totalTxBytes = 0
 	ts.totalTxGas = 0
-	ts.selectedTxs = nil
+	ts.selectedTxs = ts.selectedTxs[:0] // keep the allocated memory
 }
 
 func (ts *defaultTxSelector) SelectTxForProposal(_ context.Context, maxTxBytes, maxBlockGas uint64, memTx sdk.Tx, txBz []byte) bool {
@@ -531,3 +550,7 @@ func (ts *defaultTxSelector) SelectTxForProposal(_ context.Context, maxTxBytes,
 	// check if we've reached capacity; if so, we cannot select any more transactions
 	return ts.totalTxBytes >= maxTxBytes || (maxBlockGas > 0 && (ts.totalTxGas >= maxBlockGas))
 }
+
+func (ts *defaultTxSelector) SelectTxForProposalFast(ctx context.Context, txs [][]byte) [][]byte {
+	return txs
+}
diff --git a/baseapp/abci_utils_test.go b/baseapp/abci_utils_test.go
index a1064705f5f4..8ef3f8ea4ba2 100644
--- a/baseapp/abci_utils_test.go
+++ b/baseapp/abci_utils_test.go
@@ -478,6 +478,9 @@ func (s *ABCIUtilsTestSuite) TestDefaultProposalHandler_NoOpMempoolTxSelection()
 	ph := baseapp.NewDefaultProposalHandler(mempool.NoOpMempool{}, app)
 	handler := ph.PrepareProposalHandler()
 
+	phf := baseapp.NewDefaultProposalHandlerFast(mempool.NoOpMempool{}, app)
+	handlerFast := phf.PrepareProposalHandler()
+
 	// build a tx
 	_, _, addr := testdata.KeyTestPubAddr()
 	builder := txConfig.NewTxBuilder()
@@ -558,6 +561,10 @@ func (s *ABCIUtilsTestSuite) TestDefaultProposalHandler_NoOpMempoolTxSelection()
 				resp, err := handler(tc.ctx, tc.req)
 				s.Require().NoError(err)
 				s.Require().Len(resp.Txs, tc.expectedTxs)
+
+				resp, err = handlerFast(tc.ctx, tc.req)
+				s.Require().NoError(err)
+				s.Require().Equal(resp.Txs, tc.req.Txs)
 			}
 		})
 	}
diff --git a/baseapp/testutil/mock/mocks.go b/baseapp/testutil/mock/mocks.go
index 51de61fa7156..1cf8db2c3e7b 100644
--- a/baseapp/testutil/mock/mocks.go
+++ b/baseapp/testutil/mock/mocks.go
@@ -229,6 +229,20 @@ func (mr *MockTxSelectorMockRecorder) SelectTxForProposal(ctx, maxTxBytes, maxBl
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SelectTxForProposal", reflect.TypeOf((*MockTxSelector)(nil).SelectTxForProposal), ctx, maxTxBytes, maxBlockGas, memTx, txBz)
 }
 
+// SelectTxForProposalFast mocks base method.
+func (m *MockTxSelector) SelectTxForProposalFast(ctx context.Context, txs [][]byte) [][]byte {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "SelectTxForProposalFast", ctx, txs)
+	ret0, _ := ret[0].([][]byte)
+	return ret0
+}
+
+// SelectTxForProposalFast indicates an expected call of SelectTxForProposalFast.
+func (mr *MockTxSelectorMockRecorder) SelectTxForProposalFast(ctx, txs any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SelectTxForProposalFast", reflect.TypeOf((*MockTxSelector)(nil).SelectTxForProposalFast), ctx, txs)
+}
+
 // SelectedTxs mocks base method.
 func (m *MockTxSelector) SelectedTxs(ctx context.Context) [][]byte {
 	m.ctrl.T.Helper()