diff --git a/src/ape_ethereum/provider.py b/src/ape_ethereum/provider.py
index 21b941a859..da4a919805 100644
--- a/src/ape_ethereum/provider.py
+++ b/src/ape_ethereum/provider.py
@@ -572,7 +572,7 @@ def estimate_gas_cost(self, txn: TransactionAPI, block_id: Optional["BlockID"] =
     @cached_property
     def chain_id(self) -> int:
         default_chain_id = None
-        if (not self.network.is_adhoc and self.network.is_custom) and not self.network.is_dev:
+        if (not self.network.is_adhoc and self.network.is_custom) or not self.network.is_dev:
             # If using a live network, the chain ID is hardcoded.
             default_chain_id = self.network.chain_id