Jacob Thompson Baker (April 13, 1847 – December 7, 1919) was an American Democratic Party politician from New Jersey who represented New Jersey's 2nd congressional district for one term from 1913 to 1915.

He studied law, was admitted to the bar in 1870 and commenced practice in Lewisburg, Pennsylvania.

He was the first Mayor of Wildwood, New Jersey in 1911 and 1912, and was a delegate to the 1912 Democratic National Convention.

Baker was elected as a Democrat to the Sixty-third Congress, serving in office from March 4, 1913 to March 3, 1915, but was an unsuccessful candidate for reelection in 1914 to the Sixty-fourth Congress.

After leaving Congress, he resumed real estate activities in Wildwood.