diff --git a/ethers-core/src/types/transaction/optimism.rs b/ethers-core/src/types/transaction/optimism.rs
index ee4d397fb..6799c8c27 100644
--- a/ethers-core/src/types/transaction/optimism.rs
+++ b/ethers-core/src/types/transaction/optimism.rs
@@ -30,6 +30,7 @@ pub struct DepositTransaction {
 
     /// If true, the transaction does not interact with the L2 block gas pool.
     /// Note: boolean is disabled (enforced to be false) starting from the Regolith upgrade.
+    #[serde(rename = "isSystemTx")]
     pub is_system_tx: bool,
 }