diff --git a/clients/js-legacy/src/instructions/decode.ts b/clients/js-legacy/src/instructions/decode.ts
index 31ef2828b..cf6d52b85 100644
--- a/clients/js-legacy/src/instructions/decode.ts
+++ b/clients/js-legacy/src/instructions/decode.ts
@@ -28,6 +28,8 @@ import type { DecodedInitializeMint2Instruction } from './initializeMint2.js';
 import { decodeInitializeMint2Instruction } from './initializeMint2.js';
 import type { DecodedInitializeMultisigInstruction } from './initializeMultisig.js';
 import { decodeInitializeMultisigInstruction } from './initializeMultisig.js';
+import type { DecodedInitializeMultisig2Instruction } from './initializeMultisig2.js';
+import { decodeInitializeMultisig2Instruction } from './initializeMultisig2.js';
 import type { DecodedMintToInstruction } from './mintTo.js';
 import { decodeMintToInstruction } from './mintTo.js';
 import type { DecodedMintToCheckedInstruction } from './mintToChecked.js';
@@ -48,7 +50,7 @@ import { TokenInstruction } from './types.js';
 import type { DecodedUiAmountToAmountInstruction } from './uiAmountToAmount.js';
 import { decodeUiAmountToAmountInstruction } from './uiAmountToAmount.js';
 
-/** TODO: docs */
+/** Union type for all decoded instructions */
 export type DecodedInstruction =
     | DecodedInitializeMintInstruction
     | DecodedInitializeAccountInstruction
@@ -69,14 +71,12 @@ export type DecodedInstruction =
     | DecodedInitializeAccount2Instruction
     | DecodedSyncNativeInstruction
     | DecodedInitializeAccount3Instruction
+    | DecodedInitializeMultisig2Instruction
     | DecodedInitializeMint2Instruction
     | DecodedAmountToUiAmountInstruction
-    | DecodedUiAmountToAmountInstruction
-    // | DecodedInitializeMultisig2Instruction
-    // TODO: implement ^ and remove `never`
-    | never;
+    | DecodedUiAmountToAmountInstruction;
 
-/** TODO: docs */
+/** Decode and validate any token instruction */
 export function decodeInstruction(
     instruction: TransactionInstruction,
     programId = TOKEN_PROGRAM_ID,
@@ -106,11 +106,11 @@ export function decodeInstruction(
     if (type === TokenInstruction.SyncNative) return decodeSyncNativeInstruction(instruction, programId);
     if (type === TokenInstruction.InitializeAccount3)
         return decodeInitializeAccount3Instruction(instruction, programId);
+    if (type === TokenInstruction.InitializeMultisig2)
+        return decodeInitializeMultisig2Instruction(instruction, programId);
     if (type === TokenInstruction.InitializeMint2) return decodeInitializeMint2Instruction(instruction, programId);
     if (type === TokenInstruction.AmountToUiAmount) return decodeAmountToUiAmountInstruction(instruction, programId);
     if (type === TokenInstruction.UiAmountToAmount) return decodeUiAmountToAmountInstruction(instruction, programId);
-    // TODO: implement
-    if (type === TokenInstruction.InitializeMultisig2) throw new TokenInvalidInstructionTypeError();
 
     throw new TokenInvalidInstructionTypeError();
 }
@@ -213,21 +213,21 @@ export function isSyncNativeInstruction(decoded: DecodedInstruction): decoded is
     return decoded.data.instruction === TokenInstruction.SyncNative;
 }
 
-/** TODO: docs */
+/** Type guard to check if instruction is InitializeAccount3 */
 export function isInitializeAccount3Instruction(
     decoded: DecodedInstruction,
 ): decoded is DecodedInitializeAccount3Instruction {
     return decoded.data.instruction === TokenInstruction.InitializeAccount3;
 }
 
-/** TODO: docs, implement */
-// export function isInitializeMultisig2Instruction(
-//     decoded: DecodedInstruction
-// ): decoded is DecodedInitializeMultisig2Instruction {
-//     return decoded.data.instruction === TokenInstruction.InitializeMultisig2;
-// }
+/** Type guard to check if instruction is InitializeMultisig2 */
+export function isInitializeMultisig2Instruction(
+    decoded: DecodedInstruction,
+): decoded is DecodedInitializeMultisig2Instruction {
+    return decoded.data.instruction === TokenInstruction.InitializeMultisig2;
+}
 
-/** TODO: docs */
+/** Type guard to check if instruction is InitializeMint2 */
 export function isInitializeMint2Instruction(
     decoded: DecodedInstruction,
 ): decoded is DecodedInitializeMint2Instruction {
diff --git a/clients/js-legacy/src/instructions/initializeMultisig2.ts b/clients/js-legacy/src/instructions/initializeMultisig2.ts
index 434426c17..f4742e259 100644
--- a/clients/js-legacy/src/instructions/initializeMultisig2.ts
+++ b/clients/js-legacy/src/instructions/initializeMultisig2.ts
@@ -1 +1,141 @@
-export {}; // TODO: implement
+import { struct, u8 } from '@solana/buffer-layout';
+import type { AccountMeta, Signer } from '@solana/web3.js';
+import { PublicKey, TransactionInstruction } from '@solana/web3.js';
+import { TOKEN_PROGRAM_ID } from '../constants.js';
+import {
+    TokenInvalidInstructionDataError,
+    TokenInvalidInstructionKeysError,
+    TokenInvalidInstructionProgramError,
+    TokenInvalidInstructionTypeError,
+} from '../errors.js';
+import { TokenInstruction } from './types.js';
+
+/** InitializeMultisig2 instruction data */
+export interface InitializeMultisig2InstructionData {
+    instruction: TokenInstruction.InitializeMultisig2;
+    m: number;
+}
+
+/** InitializeMultisig2 instruction layout */
+export const initializeMultisig2InstructionData = struct<InitializeMultisig2InstructionData>([
+    u8('instruction'),
+    u8('m'),
+]);
+
+/**
+ * Construct an InitializeMultisig2 instruction
+ *
+ * @param account   Multisig account
+ * @param signers   Full set of signers
+ * @param m         Number of required signatures
+ * @param programId SPL Token program account
+ *
+ * @return Instruction to add to a transaction
+ */
+export function createInitializeMultisig2Instruction(
+    account: PublicKey,
+    signers: (Signer | PublicKey)[],
+    m: number,
+    programId = TOKEN_PROGRAM_ID,
+): TransactionInstruction {
+    const keys = [{ pubkey: account, isSigner: false, isWritable: true }];
+    for (const signer of signers) {
+        keys.push({
+            pubkey: signer instanceof PublicKey ? signer : signer.publicKey,
+            isSigner: false,
+            isWritable: false,
+        });
+    }
+
+    const data = Buffer.alloc(initializeMultisig2InstructionData.span);
+    initializeMultisig2InstructionData.encode(
+        {
+            instruction: TokenInstruction.InitializeMultisig2,
+            m,
+        },
+        data,
+    );
+
+    return new TransactionInstruction({ keys, programId, data });
+}
+
+/** A decoded, valid InitializeMultisig2 instruction */
+export interface DecodedInitializeMultisig2Instruction {
+    programId: PublicKey;
+    keys: {
+        account: AccountMeta;
+        signers: AccountMeta[];
+    };
+    data: {
+        instruction: TokenInstruction.InitializeMultisig2;
+        m: number;
+    };
+}
+
+/**
+ * Decode an InitializeMultisig2 instruction and validate it
+ *
+ * @param instruction Transaction instruction to decode
+ * @param programId   SPL Token program account
+ *
+ * @return Decoded, valid instruction
+ */
+export function decodeInitializeMultisig2Instruction(
+    instruction: TransactionInstruction,
+    programId = TOKEN_PROGRAM_ID,
+): DecodedInitializeMultisig2Instruction {
+    if (!instruction.programId.equals(programId)) throw new TokenInvalidInstructionProgramError();
+    if (instruction.data.length !== initializeMultisig2InstructionData.span)
+        throw new TokenInvalidInstructionDataError();
+
+    const {
+        keys: { account, signers },
+        data,
+    } = decodeInitializeMultisig2InstructionUnchecked(instruction);
+    if (data.instruction !== TokenInstruction.InitializeMultisig2) throw new TokenInvalidInstructionTypeError();
+    if (!account || !signers.length) throw new TokenInvalidInstructionKeysError();
+
+    return {
+        programId,
+        keys: {
+            account,
+            signers,
+        },
+        data,
+    };
+}
+
+/** A decoded, non-validated InitializeMultisig2 instruction */
+export interface DecodedInitializeMultisig2InstructionUnchecked {
+    programId: PublicKey;
+    keys: {
+        account: AccountMeta | undefined;
+        signers: AccountMeta[];
+    };
+    data: {
+        instruction: number;
+        m: number;
+    };
+}
+
+/**
+ * Decode an InitializeMultisig2 instruction without validating it
+ *
+ * @param instruction Transaction instruction to decode
+ *
+ * @return Decoded, non-validated instruction
+ */
+export function decodeInitializeMultisig2InstructionUnchecked({
+    programId,
+    keys: [account, ...signers],
+    data,
+}: TransactionInstruction): DecodedInitializeMultisig2InstructionUnchecked {
+    return {
+        programId,
+        keys: {
+            account,
+            signers,
+        },
+        data: initializeMultisig2InstructionData.decode(data),
+    };
+}