Joseph Ewing McDonald (August 29, 1819 – June 21, 1891) was an American politician who served as a United States representative and Senator from Indiana.

He also served as Indiana's 2nd Attorney General and unsuccessfully sought the Democratic nomination for President in 1884.

In 1859, He moved to Indianapolis in 1859, where he formed a law partnership with former Indiana Supreme Court Justice Addison Roache.

While in the Senate he was chairman of the Committee on Public Lands (Forty-sixth Congress).

McDonald sought his party's nomination for U.S. President at the 1884 Democratic National Convention in Chicago, but was defeated by New York Governor Grover Cleveland.