diff --git a/params/config_arbitrum.go b/params/config_arbitrum.go
index 7d48621d1e..244bcf66a3 100644
--- a/params/config_arbitrum.go
+++ b/params/config_arbitrum.go
@@ -51,6 +51,8 @@ const MaxDebugArbosVersionSupported = ArbosVersion_51
 const ArbosVersion_Dia = ArbosVersion_50
 const ArbosVersion_MultiConstraintFix = ArbosVersion_51
 
+const DefaultMaxL2MessageSize = 256 * 1024
+
 type ArbitrumChainParams struct {
 	EnableArbOS               bool
 	AllowDebugPrecompiles     bool
@@ -58,8 +60,9 @@ type ArbitrumChainParams struct {
 	InitialArbOSVersion       uint64
 	InitialChainOwner         common.Address
 	GenesisBlockNum           uint64
-	MaxCodeSize               uint64 `json:"MaxCodeSize,omitempty"`     // Maximum bytecode to permit for a contract. 0 value implies params.DefaultMaxCodeSize
-	MaxInitCodeSize           uint64 `json:"MaxInitCodeSize,omitempty"` // Maximum initcode to permit in a creation transaction and create instructions. 0 value implies params.DefaultMaxInitCodeSize
+	MaxCodeSize               uint64 `json:"MaxCodeSize,omitempty"`      // Maximum bytecode to permit for a contract. 0 value implies params.DefaultMaxCodeSize
+	MaxInitCodeSize           uint64 `json:"MaxInitCodeSize,omitempty"`  // Maximum initcode to permit in a creation transaction and create instructions. 0 value implies params.DefaultMaxInitCodeSize
+	MaxL2MessageSize          uint64 `json:"MaxL2MessageSize,omitempty"` // Maximum size of L2 message. 0 value implies DefaultMaxL2MessageSize
 }
 
 func (c *ChainConfig) IsArbitrum() bool {
@@ -88,6 +91,13 @@ func (c *ChainConfig) DebugMode() bool {
 	return c.ArbitrumChainParams.AllowDebugPrecompiles
 }
 
+func (c *ChainConfig) MaxL2MessageSize() uint64 {
+	if c.ArbitrumChainParams.MaxL2MessageSize == 0 {
+		return DefaultMaxL2MessageSize
+	}
+	return c.ArbitrumChainParams.MaxL2MessageSize
+}
+
 func (c *ChainConfig) checkArbitrumCompatible(newcfg *ChainConfig, head *big.Int) *ConfigCompatError {
 	if c.IsArbitrum() != newcfg.IsArbitrum() {
 		// This difference applies to the entire chain, so report that the genesis block is where the difference appears.