diff --git a/.changeset/pretty-cows-collect.md b/.changeset/pretty-cows-collect.md
new file mode 100644
index 0000000000..b1124283e9
--- /dev/null
+++ b/.changeset/pretty-cows-collect.md
@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Added Hashkey Chain testnet.
diff --git a/src/chains/definitions/hashkeyChainTestnet.ts b/src/chains/definitions/hashkeyChainTestnet.ts
new file mode 100644
index 0000000000..12940304c0
--- /dev/null
+++ b/src/chains/definitions/hashkeyChainTestnet.ts
@@ -0,0 +1,22 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const hashkeyTestnet = /*#__PURE__*/ defineChain({
+  id: 133,
+  name: 'HashKey Chain Testnet',
+  nativeCurrency: {
+    decimals: 18,
+    name: 'HashKey EcoPoints',
+    symbol: 'HSK',
+  },
+  rpcUrls: {
+    default: {
+      http: ['https://hashkeychain-testnet.alt.technology'],
+    },
+  },
+  blockExplorers: {
+    default: {
+      name: 'HashKey Chain Explorer',
+      url: 'https://hashkeychain-testnet-explorer.alt.technology',
+    },
+  },
+})
diff --git a/src/chains/index.ts b/src/chains/index.ts
index c135f0d451..f46169e605 100644
--- a/src/chains/index.ts
+++ b/src/chains/index.ts
@@ -133,6 +133,7 @@ export { gravity } from './definitions/gravity.js'
 export { ham } from './definitions/ham.js'
 export { hardhat } from './definitions/hardhat.js'
 export { harmonyOne } from './definitions/harmonyOne.js'
+export { hashkeyTestnet } from './definitions/hashkeyChainTestnet.js'
 export { haqqMainnet } from './definitions/haqqMainnet.js'
 export { haqqTestedge2 } from './definitions/haqqTestedge2.js'
 export { hedera } from './definitions/hedera.js'