RC3, or variants may refer to: * RC3: precision running fits, a class of engineering fit used in the United States * Republic RC-3 Seabee, an amphibious sports aircraft * , a model of SJ Rc class electric locomotive used in Sweden * , a state highway in Puducherry, India; see List of state highways in Puducherry * RC3, one of six RC algorithms, symmetric-key encryption algorithms invented by Ron Rivesta * rC3 or Remote Chaos Experience, a 2020 event of the Chaos Communication Congress * RC3 or Reginald Cornelius III, a fictional character in Knight Rider (season 4)