Robert Adams Jr. (February 26, 1849 – June 1, 1906) was an American diplomat and politician from Pennsylvania who served as a Republican member of the U.S. House of Representatives for Pennsylvania's 2nd congressional district from 1893 to 1906. He served as the United States Minister to Brazil from 1889 to 1890 and as a member of the Pennsylvania State Senate for the 6th district from 1883 to 1885.