diff --git a/web3.js/examples/budget.js b/web3.js/examples/budget.js
index 25cf71fc10..2f9c37ab61 100644
--- a/web3.js/examples/budget.js
+++ b/web3.js/examples/budget.js
@@ -54,12 +54,12 @@ showBalance()
 .then(showBalance)
 .then(() => {
   console.log(`\n== Creating account for the contract funds`);
-  const transaction = solanaWeb3.SystemContract.createAccount(
+  const transaction = solanaWeb3.SystemProgram.createAccount(
     account1.publicKey,
     contractFunds.publicKey,
     50, // number of tokens to transfer
     0,
-    solanaWeb3.BudgetContract.contractId,
+    solanaWeb3.BudgetProgram.programId,
   );
   return connection.sendTransaction(account1, transaction);
 })
@@ -67,12 +67,12 @@ showBalance()
 .then(showBalance)
 .then(() => {
   console.log(`\n== Creating account for the contract state`);
-  const transaction = solanaWeb3.SystemContract.createAccount(
+  const transaction = solanaWeb3.SystemProgram.createAccount(
     account1.publicKey,
     contractState.publicKey,
-    1, // sender pays 1 token to hold the contract state
-    solanaWeb3.BudgetContract.space,
-    solanaWeb3.BudgetContract.contractId,
+    1, // account1 pays 1 token to hold the contract state
+    solanaWeb3.BudgetProgram.space,
+    solanaWeb3.BudgetProgram.programId,
   );
   return connection.sendTransaction(account1, transaction);
 })
@@ -80,12 +80,12 @@ showBalance()
 .then(showBalance)
 .then(() => {
   console.log(`\n== Initializing contract`);
-  const transaction = solanaWeb3.BudgetContract.pay(
+  const transaction = solanaWeb3.BudgetProgram.pay(
     contractFunds.publicKey,
     contractState.publicKey,
     account2.publicKey,
     50,
-    solanaWeb3.BudgetContract.timestampCondition(account1.publicKey, new Date("2050")),
+    solanaWeb3.BudgetProgram.timestampCondition(account1.publicKey, new Date('2050')),
   );
   return connection.sendTransaction(contractFunds, transaction);
 })
@@ -93,11 +93,11 @@ showBalance()
 .then(showBalance)
 .then(() => {
   console.log(`\n== Witness contract`);
-  const transaction = solanaWeb3.BudgetContract.applyTimestamp(
+  const transaction = solanaWeb3.BudgetProgram.applyTimestamp(
     account1.publicKey,
     contractState.publicKey,
     account2.publicKey,
-    new Date("2050"),
+    new Date('2050'),
   );
   return connection.sendTransaction(account1, transaction);
 })
diff --git a/web3.js/src/budget-contract.js b/web3.js/src/budget-program.js
similarity index 93%
rename from web3.js/src/budget-contract.js
rename to web3.js/src/budget-program.js
index 08fa8357c1..78bb40f317 100644
--- a/web3.js/src/budget-contract.js
+++ b/web3.js/src/budget-program.js
@@ -107,19 +107,19 @@ function serializeCondition(condition: BudgetCondition) {
 
 
 /**
- * Factory class for transactions to interact with the Budget contract
+ * Factory class for transactions to interact with the Budget program
  */
-export class BudgetContract {
+export class BudgetProgram {
 
   /**
-   * Public key that identifies the Budget Contract
+   * Public key that identifies the Budget program
    */
-  static get contractId(): PublicKey {
+  static get programId(): PublicKey {
     return '4uQeVj5tqViQh7yWWGStvkEG1Zmhx6uasJtWCJziofM';
   }
 
   /**
-   * The amount of space this contract requires
+   * The amount of space this program requires
    */
   static get space(): number {
     return 128;
@@ -184,7 +184,7 @@ export class BudgetContract {
       return new Transaction({
         fee: 0,
         keys: [from, to],
-        contractId: this.contractId,
+        programId: this.programId,
         userdata: userdata.slice(0, pos),
       });
     case 1:
@@ -205,7 +205,7 @@ export class BudgetContract {
       return new Transaction({
         fee: 0,
         keys: [from, contract, to],
-        contractId: this.contractId,
+        programId: this.programId,
         userdata: userdata.slice(0, pos),
       });
 
@@ -226,7 +226,7 @@ export class BudgetContract {
       return new Transaction({
         fee: 0,
         keys: [from, contract, to],
-        contractId: this.contractId,
+        programId: this.programId,
         userdata: userdata.slice(0, pos),
       });
 
@@ -245,7 +245,7 @@ export class BudgetContract {
     return new Transaction({
       fee: 0,
       keys: [from, contract, to],
-      contractId: this.contractId,
+      programId: this.programId,
       userdata,
     });
   }
@@ -257,7 +257,7 @@ export class BudgetContract {
     return new Transaction({
       fee: 0,
       keys: [from, contract, to],
-      contractId: this.contractId,
+      programId: this.programId,
       userdata,
     });
   }
diff --git a/web3.js/src/index.js b/web3.js/src/index.js
index 3bc0faff0d..f613a2d68d 100644
--- a/web3.js/src/index.js
+++ b/web3.js/src/index.js
@@ -2,5 +2,5 @@
 export {Account} from './account';
 export {Connection} from './connection';
 export {Transaction} from './transaction';
-export {SystemContract} from './system-contract';
-export {BudgetContract} from './budget-contract';
+export {SystemProgram} from './system-program';
+export {BudgetProgram} from './budget-program';
diff --git a/web3.js/src/system-contract.js b/web3.js/src/system-program.js
similarity index 69%
rename from web3.js/src/system-contract.js
rename to web3.js/src/system-program.js
index b2ccd2992b..2bbd00fa00 100644
--- a/web3.js/src/system-contract.js
+++ b/web3.js/src/system-program.js
@@ -6,13 +6,13 @@ import {Transaction} from './transaction';
 import type {PublicKey} from './account';
 
 /**
- * Factory class for transactions to interact with the System contract
+ * Factory class for transactions to interact with the System program
  */
-export class SystemContract {
+export class SystemProgram {
   /**
-   * Public key that identifies the System Contract
+   * Public key that identifies the System program
    */
-  static get contractId(): PublicKey {
+  static get programId(): PublicKey {
     return '11111111111111111111111111111111';
   }
 
@@ -24,7 +24,7 @@ export class SystemContract {
     newAccount: PublicKey,
     tokens: number,
     space: number,
-    contractId: ?PublicKey
+    programId: ?PublicKey
   ): Transaction {
     const userdata = Buffer.alloc(4 + 8 + 8 + 1 + 32);
     let pos = 0;
@@ -38,12 +38,12 @@ export class SystemContract {
     userdata.writeUInt32LE(space, pos); // space as u64
     pos += 8;
 
-    if (contractId) {
+    if (programId) {
       userdata.writeUInt8(1, pos); // 'Some'
       pos += 1;
 
-      const contractIdBytes = Transaction.serializePublicKey(contractId);
-      contractIdBytes.copy(userdata, pos);
+      const programIdBytes = Transaction.serializePublicKey(programId);
+      programIdBytes.copy(userdata, pos);
       pos += 32;
     } else {
       userdata.writeUInt8(0, pos); // 'None'
@@ -55,7 +55,7 @@ export class SystemContract {
     return new Transaction({
       fee: 0,
       keys: [from, newAccount],
-      contractId: SystemContract.contractId,
+      programId: SystemProgram.programId,
       userdata,
     });
   }
@@ -77,31 +77,31 @@ export class SystemContract {
     return new Transaction({
       fee: 0,
       keys: [from, to],
-      contractId: SystemContract.contractId,
+      programId: SystemProgram.programId,
       userdata,
     });
   }
 
   /**
-   * Generate a Transaction that assigns an account to a contract id
+   * Generate a Transaction that assigns an account to a program
    */
-  static assign(from: PublicKey, contractId: PublicKey): Transaction {
+  static assign(from: PublicKey, programId: PublicKey): Transaction {
     const userdata = Buffer.alloc(4 + 32);
     let pos = 0;
 
     userdata.writeUInt32LE(1, pos); // Assign instruction
     pos += 4;
 
-    const contractIdBytes = Transaction.serializePublicKey(contractId);
-    contractIdBytes.copy(userdata, pos);
-    pos += contractIdBytes.length;
+    const programIdBytes = Transaction.serializePublicKey(programId);
+    programIdBytes.copy(userdata, pos);
+    pos += programIdBytes.length;
 
     assert(pos === userdata.length);
 
     return new Transaction({
       fee: 0,
       keys: [from],
-      contractId: SystemContract.contractId,
+      programId: SystemProgram.programId,
       userdata,
     });
   }
diff --git a/web3.js/src/transaction.js b/web3.js/src/transaction.js
index 9be1837627..aa9faff12e 100644
--- a/web3.js/src/transaction.js
+++ b/web3.js/src/transaction.js
@@ -22,7 +22,7 @@ export type TransactionId = string;
 type TransactionCtorFields = {|
   signature?: Buffer;
   keys?: Array<PublicKey>;
-  contractId?: PublicKey;
+  programId?: PublicKey;
   fee?: number;
   userdata?: Buffer;
 |};
@@ -44,9 +44,9 @@ export class Transaction {
   keys: Array<PublicKey> = [];
 
   /**
-   * Contract Id to execute
+   * Program Id to execute
    */
-  contractId: ?PublicKey;
+  programId: ?PublicKey;
 
   /**
    * A recent transaction id.  Must be populated by the caller
@@ -59,7 +59,7 @@ export class Transaction {
   fee: number = 0;
 
   /**
-   * Contract input userdata to include
+   * Program input
    */
   userdata: Buffer = Buffer.alloc(0);
 
@@ -90,9 +90,9 @@ export class Transaction {
       pos += 32;
     }
 
-    // serialize `this.contractId`
-    if (this.contractId) {
-      const keyBytes = Transaction.serializePublicKey(this.contractId);
+    // serialize `this.programId`
+    if (this.programId) {
+      const keyBytes = Transaction.serializePublicKey(this.programId);
       keyBytes.copy(transactionData, pos);
     }
     pos += 32;
diff --git a/web3.js/test/budget-contract.test.js b/web3.js/test/budget-program.test.js
similarity index 60%
rename from web3.js/test/budget-contract.test.js
rename to web3.js/test/budget-program.test.js
index f87153b574..b5b2381c34 100644
--- a/web3.js/test/budget-contract.test.js
+++ b/web3.js/test/budget-program.test.js
@@ -1,7 +1,7 @@
 // @flow
 
 import {Account} from '../src/account';
-import {BudgetContract} from '../src/budget-contract';
+import {BudgetProgram} from '../src/budget-program';
 
 test('pay', () => {
   const from = new Account();
@@ -9,7 +9,7 @@ test('pay', () => {
   const to = new Account();
   let transaction;
 
-  transaction = BudgetContract.pay(
+  transaction = BudgetProgram.pay(
     from.publicKey,
     contract.publicKey,
     to.publicKey,
@@ -17,22 +17,22 @@ test('pay', () => {
   );
   console.log('Pay:', transaction);
 
-  transaction = BudgetContract.pay(
+  transaction = BudgetProgram.pay(
     from.publicKey,
     contract.publicKey,
     to.publicKey,
     123,
-    BudgetContract.signatureCondition(from.publicKey),
+    BudgetProgram.signatureCondition(from.publicKey),
   );
   console.log('After:', transaction);
 
-  transaction = BudgetContract.pay(
+  transaction = BudgetProgram.pay(
     from.publicKey,
     contract.publicKey,
     to.publicKey,
     123,
-    BudgetContract.signatureCondition(from.publicKey),
-    BudgetContract.timestampCondition(from.publicKey, new Date()),
+    BudgetProgram.signatureCondition(from.publicKey),
+    BudgetProgram.timestampCondition(from.publicKey, new Date()),
   );
   console.log('Or:', transaction);
 });
diff --git a/web3.js/test/connection.test.js b/web3.js/test/connection.test.js
index f832b28be9..6eabe34705 100644
--- a/web3.js/test/connection.test.js
+++ b/web3.js/test/connection.test.js
@@ -2,7 +2,7 @@
 
 import {Account} from '../src/account';
 import {Connection} from '../src/connection';
-import {SystemContract} from '../src/system-contract';
+import {SystemProgram} from '../src/system-program';
 import {mockRpc} from './__mocks__/node-fetch';
 
 const url = 'http://testnet.solana.com:8899';
@@ -274,7 +274,7 @@ test('transaction', async () => {
   ]
   );
 
-  const transaction = SystemContract.move(
+  const transaction = SystemProgram.move(
     accountFrom.publicKey,
     accountTo.publicKey,
     10