diff --git a/src/index.ts b/src/index.ts
index 083567c..b800f4b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -50,5 +50,5 @@ export {
   anchorTrustHash,
   verifyEventHash,
 } from './escrow';
-export { buildMultisigTransaction } from './transactions';
+export { buildMultisigTransaction, buildSetOptionsOp } from './transactions';
 export { getMinimumReserve, generateKeypair } from './accounts';
diff --git a/src/transactions/builder.ts b/src/transactions/builder.ts
new file mode 100644
index 0000000..98b3505
--- /dev/null
+++ b/src/transactions/builder.ts
@@ -0,0 +1,77 @@
+import { Operation, xdr } from '@stellar/stellar-sdk';
+
+import { ValidationError } from '../utils/errors';
+import { isValidPublicKey } from '../utils/validation';
+
+export interface SetOptionsSignerInput {
+  publicKey: string;
+  weight: number;
+}
+
+export interface SetOptionsThresholdsInput {
+  low: number;
+  medium: number;
+  high: number;
+}
+
+export interface BuildSetOptionsOpParams {
+  signers?: SetOptionsSignerInput[];
+  thresholds?: SetOptionsThresholdsInput;
+  masterWeight?: number;
+}
+
+function validateUint8Field(field: string, value: number): void {
+  if (!Number.isInteger(value) || value < 0 || value > 255) {
+    throw new ValidationError(field, 'Must be an integer between 0 and 255');
+  }
+}
+
+export function buildSetOptionsOp(params: BuildSetOptionsOpParams): xdr.Operation[] {
+  const operations: xdr.Operation[] = [];
+
+  if (params.signers) {
+    params.signers.forEach((signer, index) => {
+      if (!isValidPublicKey(signer.publicKey)) {
+        throw new ValidationError(`signers[${index}].publicKey`, 'Invalid public key');
+      }
+
+      validateUint8Field(`signers[${index}].weight`, signer.weight);
+
+      operations.push(
+        Operation.setOptions({
+          signer: {
+            ed25519PublicKey: signer.publicKey,
+            weight: signer.weight,
+          },
+        }),
+      );
+    });
+  }
+
+  if (params.masterWeight !== undefined) {
+    validateUint8Field('masterWeight', params.masterWeight);
+  }
+
+  if (params.thresholds) {
+    validateUint8Field('thresholds.low', params.thresholds.low);
+    validateUint8Field('thresholds.medium', params.thresholds.medium);
+    validateUint8Field('thresholds.high', params.thresholds.high);
+  }
+
+  if (params.masterWeight !== undefined || params.thresholds) {
+    operations.push(
+      Operation.setOptions({
+        ...(params.masterWeight !== undefined ? { masterWeight: params.masterWeight } : {}),
+        ...(params.thresholds
+          ? {
+              lowThreshold: params.thresholds.low,
+              medThreshold: params.thresholds.medium,
+              highThreshold: params.thresholds.high,
+            }
+          : {}),
+      }),
+    );
+  }
+
+  return operations;
+}
\ No newline at end of file
diff --git a/src/transactions/index.ts b/src/transactions/index.ts
index 3a7c3cb..095d3c8 100644
--- a/src/transactions/index.ts
+++ b/src/transactions/index.ts
@@ -1,6 +1,7 @@
 
 import { HorizonSubmitError } from '../utils/errors';
 import { TESTNET_HORIZON_URL } from '../utils/constants';
+export { buildSetOptionsOp } from './builder';
 
 /**
  * Internal: Fetch a single transaction status from Horizon by hash.
diff --git a/tests/unit/transactions/index.test.ts b/tests/unit/transactions/index.test.ts
index e387720..faf251a 100644
--- a/tests/unit/transactions/index.test.ts
+++ b/tests/unit/transactions/index.test.ts
@@ -1,6 +1,8 @@
 
-import { buildMultisigTransaction, fetchTransactionOnce } from '../../../src/transactions';
-import { HorizonSubmitError } from '../../../src/utils/errors';
+import { Keypair, Operation } from '@stellar/stellar-sdk';
+
+import { buildMultisigTransaction, buildSetOptionsOp, fetchTransactionOnce } from '../../../src/transactions';
+import { HorizonSubmitError, ValidationError } from '../../../src/utils/errors';
 
 describe('transactions module placeholders', () => {
   it('exports callable placeholder function', () => {
@@ -8,6 +10,89 @@ describe('transactions module placeholders', () => {
   });
 });
 
+describe('buildSetOptionsOp', () => {
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  it('builds setOptions operation for adding a signer', () => {
+    const signerPublicKey = Keypair.random().publicKey();
+    const setOptionsSpy = jest.spyOn(Operation, 'setOptions');
+
+    const operations = buildSetOptionsOp({
+      signers: [{ publicKey: signerPublicKey, weight: 1 }],
+    });
+
+    expect(operations).toHaveLength(1);
+    expect(setOptionsSpy).toHaveBeenCalledWith({
+      signer: { ed25519PublicKey: signerPublicKey, weight: 1 },
+    });
+  });
+
+  it('builds setOptions operation for removing a signer with weight 0', () => {
+    const signerPublicKey = Keypair.random().publicKey();
+    const setOptionsSpy = jest.spyOn(Operation, 'setOptions');
+
+    const operations = buildSetOptionsOp({
+      signers: [{ publicKey: signerPublicKey, weight: 0 }],
+    });
+
+    expect(operations).toHaveLength(1);
+    expect(setOptionsSpy).toHaveBeenCalledWith({
+      signer: { ed25519PublicKey: signerPublicKey, weight: 0 },
+    });
+  });
+
+  it('builds setOptions operation for thresholds', () => {
+    const setOptionsSpy = jest.spyOn(Operation, 'setOptions');
+
+    const operations = buildSetOptionsOp({
+      thresholds: { low: 1, medium: 2, high: 3 },
+    });
+
+    expect(operations).toHaveLength(1);
+    expect(setOptionsSpy).toHaveBeenCalledWith({
+      lowThreshold: 1,
+      medThreshold: 2,
+      highThreshold: 3,
+    });
+  });
+
+  it('builds mixed setOptions operations for signers and thresholds', () => {
+    const signerPublicKey = Keypair.random().publicKey();
+    const setOptionsSpy = jest.spyOn(Operation, 'setOptions');
+
+    const operations = buildSetOptionsOp({
+      signers: [{ publicKey: signerPublicKey, weight: 2 }],
+      thresholds: { low: 1, medium: 2, high: 2 },
+      masterWeight: 0,
+    });
+
+    expect(operations).toHaveLength(2);
+    expect(setOptionsSpy).toHaveBeenNthCalledWith(1, {
+      signer: { ed25519PublicKey: signerPublicKey, weight: 2 },
+    });
+    expect(setOptionsSpy).toHaveBeenNthCalledWith(2, {
+      masterWeight: 0,
+      lowThreshold: 1,
+      medThreshold: 2,
+      highThreshold: 2,
+    });
+  });
+
+  it('throws ValidationError when a signer public key is invalid', () => {
+    const setOptionsSpy = jest.spyOn(Operation, 'setOptions');
+
+    expect(() =>
+      buildSetOptionsOp({
+        signers: [{ publicKey: 'INVALID_PUBLIC_KEY', weight: 1 }],
+      }),
+    ).toThrow(ValidationError);
+
+    expect(setOptionsSpy).not.toHaveBeenCalled();
+  });
+});
+
 describe('fetchTransactionOnce', () => {
   const hash = 'abc123';
   const baseUrl = 'https://horizon-testnet.stellar.org/transactions/';