diff --git a/.changeset/many-tomatoes-cheat.md b/.changeset/many-tomatoes-cheat.md
new file mode 100644
index 0000000000..a1d95ec357
--- /dev/null
+++ b/.changeset/many-tomatoes-cheat.md
@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Added Haust Network Testnet.
diff --git a/src/chains/definitions/hashkeyChainTestnet.ts b/src/chains/definitions/hashkeyChainTestnet.ts
index 12940304c0..e40af0376a 100644
--- a/src/chains/definitions/hashkeyChainTestnet.ts
+++ b/src/chains/definitions/hashkeyChainTestnet.ts
@@ -19,4 +19,5 @@ export const hashkeyTestnet = /*#__PURE__*/ defineChain({
       url: 'https://hashkeychain-testnet-explorer.alt.technology',
     },
   },
+  testnet: true,
 })
diff --git a/src/chains/definitions/haustTestnet.ts b/src/chains/definitions/haustTestnet.ts
new file mode 100644
index 0000000000..a2a71da53f
--- /dev/null
+++ b/src/chains/definitions/haustTestnet.ts
@@ -0,0 +1,23 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const haustTestnet = /*#__PURE__*/ defineChain({
+  id: 1_523_903_251,
+  name: 'Haust Network Testnet',
+  nativeCurrency: {
+    decimals: 18,
+    name: 'HAUST',
+    symbol: 'HAUST',
+  },
+  rpcUrls: {
+    default: {
+      http: ['https://rpc-testnet.haust.app'],
+    },
+  },
+  blockExplorers: {
+    default: {
+      name: 'Haust Network Testnet Explorer',
+      url: 'https://explorer-testnet.haust.app',
+    },
+  },
+  testnet: true,
+})
diff --git a/src/chains/index.ts b/src/chains/index.ts
index 435cd909c0..d6fc6b828c 100644
--- a/src/chains/index.ts
+++ b/src/chains/index.ts
@@ -208,6 +208,7 @@ export { hardhat } from './definitions/hardhat.js'
 export { harmonyOne } from './definitions/harmonyOne.js'
 export { hashkey } from './definitions/hashKeyChain.js'
 export { hashkeyTestnet } from './definitions/hashkeyChainTestnet.js'
+export { haustTestnet } from './definitions/haustTestnet.js'
 export { hedera } from './definitions/hedera.js'
 export { hederaPreviewnet } from './definitions/hederaPreviewnet.js'
 export { hederaTestnet } from './definitions/hederaTestnet.js'