diff --git a/.changeset/arc-testnet-decimals.md b/.changeset/arc-testnet-decimals.md
new file mode 100644
index 00000000000..4edf1aee674
--- /dev/null
+++ b/.changeset/arc-testnet-decimals.md
@@ -0,0 +1,5 @@
+---
+"thirdweb": patch
+---
+
+Fix Arc Testnet native currency decimals (USDC) from 6 to 18 to match the chain's RPC balance encoding
diff --git a/packages/thirdweb/src/chains/chain-definitions/arc-testnet.ts b/packages/thirdweb/src/chains/chain-definitions/arc-testnet.ts
index 3f67513ebbb..5a306c2244f 100644
--- a/packages/thirdweb/src/chains/chain-definitions/arc-testnet.ts
+++ b/packages/thirdweb/src/chains/chain-definitions/arc-testnet.ts
@@ -12,6 +12,6 @@ export const arcTestnet = /* @__PURE__ */ defineChain({
   ],
   id: 5042002,
   name: "Arc Testnet",
-  nativeCurrency: { decimals: 6, name: "USDC", symbol: "USDC" },
+  nativeCurrency: { decimals: 18, name: "USDC", symbol: "USDC" },
   testnet: true,
 });