diff --git a/bolt-sidecar/src/client/rpc.rs b/bolt-sidecar/src/client/rpc.rs
index ec796167..a5981eb6 100644
--- a/bolt-sidecar/src/client/rpc.rs
+++ b/bolt-sidecar/src/client/rpc.rs
@@ -33,6 +33,11 @@ impl RpcClient {
         Self(client)
     }
 
+    /// Get the chain ID.
+    pub async fn get_chain_id(&self) -> TransportResult<u64> {
+        self.0.request("eth_chainId", ()).await
+    }
+
     /// Get the basefee of the latest block.
     pub async fn get_basefee(&self, block_number: Option<u64>) -> TransportResult<u128> {
         let tag = block_number.map_or(BlockNumberOrTag::Latest, BlockNumberOrTag::Number);
diff --git a/bolt-sidecar/src/primitives/commitment.rs b/bolt-sidecar/src/primitives/commitment.rs
index c220ad37..cbe9e63b 100644
--- a/bolt-sidecar/src/primitives/commitment.rs
+++ b/bolt-sidecar/src/primitives/commitment.rs
@@ -42,6 +42,15 @@ impl InclusionRequest {
         }
         true
     }
+
+    /// Validates the transaction chain id against the provided chain id.
+    /// Returns true if the chain id matches, false otherwise.
+    pub fn validate_chain_id(&self, chain_id: u64) -> bool {
+        match self.tx.chain_id() {
+            Some(tx_chain_id) if tx_chain_id == chain_id => true,
+            _ => false,
+        }
+    }
 }
 
 fn deserialize_tx_signed<'de, D>(deserializer: D) -> Result<TransactionSigned, D::Error>
diff --git a/bolt-sidecar/src/state/execution.rs b/bolt-sidecar/src/state/execution.rs
index 4dd74601..ad01b143 100644
--- a/bolt-sidecar/src/state/execution.rs
+++ b/bolt-sidecar/src/state/execution.rs
@@ -37,6 +37,9 @@ pub enum ValidationError {
     /// Could not recover signature,
     #[error("Could not recover signer")]
     RecoverSigner,
+    /// The transaction chain ID does not match the expected chain ID.
+    #[error("Chain ID mismatch")]
+    ChainIdMismatch,
     /// NOTE: this should not be exposed to the user.
     #[error("Internal error: {0}")]
     Internal(String),
@@ -79,6 +82,9 @@ pub struct ExecutionState<C> {
     /// proposal duties for a single lookahead.
     block_templates: HashMap<Slot, BlockTemplate>,
 
+    /// The chain ID of the chain (constant).
+    chain_id: u64,
+
     /// The state fetcher client.
     client: C,
 }
@@ -93,6 +99,7 @@ impl<C: StateFetcher> ExecutionState<C> {
             slot: 0,
             account_states: HashMap::new(),
             block_templates: HashMap::new(),
+            chain_id: client.get_chain_id().await?,
             client,
         })
     }
@@ -118,6 +125,11 @@ impl<C: StateFetcher> ExecutionState<C> {
     pub async fn try_commit(&mut self, request: &CommitmentRequest) -> Result<(), ValidationError> {
         let CommitmentRequest::Inclusion(req) = request;
 
+        // Validate the chain ID
+        if !req.validate_chain_id(self.chain_id) {
+            return Err(ValidationError::ChainIdMismatch);
+        }
+
         let sender = req.tx.recover_signer().ok_or(ValidationError::Internal(
             "Failed to recover signer from transaction".to_string(),
         ))?;
diff --git a/bolt-sidecar/src/state/fetcher.rs b/bolt-sidecar/src/state/fetcher.rs
index 58957978..2df3b150 100644
--- a/bolt-sidecar/src/state/fetcher.rs
+++ b/bolt-sidecar/src/state/fetcher.rs
@@ -38,6 +38,8 @@ pub trait StateFetcher {
         address: &Address,
         block_number: Option<u64>,
     ) -> Result<AccountState, TransportError>;
+
+    async fn get_chain_id(&self) -> Result<u64, TransportError>;
 }
 
 /// A basic state fetcher that uses an RPC client to fetch state updates.
@@ -177,6 +179,10 @@ impl StateFetcher for StateClient {
             }
         }
     }
+
+    async fn get_chain_id(&self) -> Result<u64, TransportError> {
+        self.client.get_chain_id().await
+    }
 }
 
 #[cfg(test)]