diff --git a/internal/ethapi/transaction_args.go b/internal/ethapi/transaction_args.go
index 1a7cf1c118..586df48759 100644
--- a/internal/ethapi/transaction_args.go
+++ b/internal/ethapi/transaction_args.go
@@ -195,6 +195,12 @@ func (args *TransactionArgs) setFeeDefaults(ctx context.Context, b Backend, head
 	if args.GasPrice != nil && (args.MaxFeePerGas != nil || args.MaxPriorityFeePerGas != nil) {
 		return errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
 	}
+	// An EIP-7702 set-code transaction cannot be a legacy transaction, so gasPrice
+	// is incompatible with an authorization list. Reject the combination instead of
+	// silently dropping the authorization list in ToTransaction.
+	if args.GasPrice != nil && args.AuthorizationList != nil {
+		return errors.New("both gasPrice and authorizationList specified")
+	}
 	// If the tx has completely specified a fee mechanism, no default is needed.
 	// This allows users who are not yet synced past London to get defaults for
 	// other tx values. See https://github.com/ethereum/go-ethereum/pull/23274
diff --git a/internal/ethapi/transaction_args_test.go b/internal/ethapi/transaction_args_test.go
index f3fc16dcbb..1d587032bb 100644
--- a/internal/ethapi/transaction_args_test.go
+++ b/internal/ethapi/transaction_args_test.go
@@ -58,6 +58,7 @@ func TestSetFeeDefaults(t *testing.T) {
 		fortytwo = (*hexutil.Big)(big.NewInt(42))
 		maxFee   = (*hexutil.Big)(new(big.Int).Add(new(big.Int).Mul(b.current.BaseFee, big.NewInt(2)), fortytwo.ToInt()))
 		al       = &types.AccessList{types.AccessTuple{Address: common.Address{0xaa}, StorageKeys: []common.Hash{{0x01}}}}
+		authList = []types.SetCodeAuthorization{{Address: common.Address{0xbb}}}
 	)
 
 	tests := []test{
@@ -208,6 +209,13 @@ func TestSetFeeDefaults(t *testing.T) {
 			nil,
 			errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified"),
 		},
+		{
+			"set gas price and authorization list",
+			"london",
+			&TransactionArgs{GasPrice: fortytwo, AuthorizationList: authList},
+			nil,
+			errors.New("both gasPrice and authorizationList specified"),
+		},
 		// EIP-4844
 		{
 			"set gas price and maxFee for blob transaction",