The 1980 United States Senate elections were held on November 4, coinciding with Ronald Reagan's victory in the presidential election. The 34 Senate seats of Class 3 were contested in regular elections. Reagan's large margin of victory over incumbent Jimmy Carter gave a huge boost to Republican Senate candidates, allowing them to flip 12 Democratic seats and win control of the chamber for the first time since the end of the 83rd Congress in January 1955.

Ronald Wilson Reagan was an American politician and actor who served as the 40th president of the United States from 1981 to 1989. A member of the Republican Party, his presidency constituted the Reagan era, and he is considered one of the most prominent conservative figures in American history.