List of Republicans who opposed the Donald Trump 2020 presidential campaign

This is a list of Republicans and conservatives who opposed the re-election of incumbent Donald Trump, the 2020 Republican Party nominee for President of the United States. Among them are former Republicans who left the party in 2016 or later due to their opposition to Trump, those who held office as a Republican, Republicans who endorsed a different candidate, and Republican presidential primary election candidates that announced opposition to Trump as the presumptive nominee. Over 70 former senior Republican national security officials and 61 additional senior officials have also signed onto a statement declaring, "We are profoundly concerned about our nation's security and standing in the world under the leadership of Donald Trump. The President has demonstrated that he is dangerously unfit to serve another term."

A group of former senior U.S. government officials and conservatives—including from the Reagan, Bush 41, Bush 43, and Trump administrations formed The Republican Political Alliance for Integrity and Reform (REPAIR) to, "focus on a return to principles-based governing in the post-Trump era." A third group of Republicans, Republican Voters Against Trump was launched in May 2020 collected over 500 testimonials opposing Trump.