diff --git a/packages/walletkit/package.json b/packages/walletkit/package.json
index e78c81721..8b8c5b4fb 100644
--- a/packages/walletkit/package.json
+++ b/packages/walletkit/package.json
@@ -61,6 +61,7 @@
     "@tonconnect/protocol": "^2.3.0",
     "@tonconnect/sdk": "^3.2.0",
     "@truecarry/tlb-abi": "^0.2.0",
+    "bip39": "^3.1.0",
     "lru-cache": "^11.1.0",
     "node-hid": "^3.2.0",
     "vite": "^7.1.3"
diff --git a/packages/walletkit/src/utils/mnemonic.ts b/packages/walletkit/src/utils/mnemonic.ts
index aff0a7d9b..4cc14d3f5 100644
--- a/packages/walletkit/src/utils/mnemonic.ts
+++ b/packages/walletkit/src/utils/mnemonic.ts
@@ -1,18 +1,31 @@
-import { mnemonicToWalletKey, mnemonicNew } from '@ton/crypto';
+import { mnemonicToWalletKey, mnemonicNew, keyPairFromSeed, deriveEd25519Path } from '@ton/crypto';
+import { mnemonicToSeed as bip39MnemonicToSeed } from 'bip39';
 
 import { WalletKitError, ERROR_CODES } from '../errors';
 
+async function bip39ToPrivateKey(mnemonic: string[]) {
+    const seed = await bip39MnemonicToSeed(mnemonic.join(' '));
+    const TON_DERIVATION_PATH = [44, 607, 0];
+    const seedContainer = await deriveEd25519Path(seed, TON_DERIVATION_PATH);
+    return keyPairFromSeed(seedContainer.subarray(0, 32));
+}
+
+/**
+ * Convert a mnemonic to a key pair
+ * @param mnemonic - The mnemonic to convert, can be an array of strings or a string. 12 or 24 words
+ * @param mnemonicType - The type of mnemonic to convert, can be 'ton' or 'bip39'
+ * @returns The key pair
+ */
 export async function MnemonicToKeyPair(
     mnemonic: string | string[],
     mnemonicType: 'ton' | 'bip39' = 'ton',
 ): Promise<{ publicKey: Uint8Array; secretKey: Uint8Array }> {
     const mnemonicArray = Array.isArray(mnemonic) ? mnemonic : mnemonic.split(' ');
-    if (mnemonicArray.length !== 24) {
+
+    if (mnemonicArray.length !== 12 && mnemonicArray.length !== 24) {
         throw new WalletKitError(
             ERROR_CODES.VALIDATION_ERROR,
-            `Invalid mnemonic length: expected 24 words, got ${mnemonicArray.length}`,
-            undefined,
-            { receivedLength: mnemonicArray.length, expectedLength: 24 },
+            `Invalid mnemonic length: expected 12 or 24 words, got ${mnemonicArray.length}`,
         );
     }
 
@@ -24,7 +37,13 @@ export async function MnemonicToKeyPair(
         };
     }
 
-    // TODO bip39 support
+    if (mnemonicType === 'bip39') {
+        const key = await bip39ToPrivateKey(mnemonicArray);
+        return {
+            publicKey: new Uint8Array(key.publicKey),
+            secretKey: new Uint8Array(key.secretKey),
+        };
+    }
 
     throw new WalletKitError(
         ERROR_CODES.VALIDATION_ERROR,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 7682fdef0..487ec5d9b 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -242,6 +242,9 @@ importers:
       '@truecarry/tlb-abi':
         specifier: ^0.2.0
         version: 0.2.0(@ton/core@0.61.0(@ton/crypto@3.3.0))
+      bip39:
+        specifier: ^3.1.0
+        version: 3.1.0
       lru-cache:
         specifier: ^11.1.0
         version: 11.1.0
@@ -2380,6 +2383,9 @@ packages:
   bindings@1.5.0:
     resolution: {integrity: sha512-p2q/t/mhvuOj/UeLlV6566GD/guowlr0hHxClI0W9m7MWYkL1F0hLo+0Aexs9HSPCtR1SXQ0TD3MMKrXZajbiQ==}
 
+  bip39@3.1.0:
+    resolution: {integrity: sha512-c9kiwdk45Do5GL0vJMe7tS95VjCii65mYAH7DfWl3uW8AVzXKQVUm64i3hzVybBDMp9r7j9iNxR85+ul8MdN/A==}
+
   bl@4.1.0:
     resolution: {integrity: sha512-1W07cM9gS6DcLperZfFSj+bWLtaPGSOHWhPiGzXmvVJbRLdG82sH/Kn8EtW1VqWVA54AKf2h5k5BbnIbwF3h6w==}
 
@@ -8798,6 +8804,10 @@ snapshots:
     dependencies:
       file-uri-to-path: 1.0.0
 
+  bip39@3.1.0:
+    dependencies:
+      '@noble/hashes': 1.8.0
+
   bl@4.1.0:
     dependencies:
       buffer: 5.7.1