Pacer, PACER or Pacers can refer to:
- PACER (law), a United States government legal documentation system standing for Public Access to Court Electronic Records
- PACER (fusion), 1970s nuclear power project at Los Alamos National Laboratory in the United States
- Pacific Agreement on Closer Economic Relations, international trade cooperation agreement
- Transport
- AMC Pacer, an American car produced by the American Motors Corporation
- Edsel Pacer, an American car produced by Ford
- Piper PA-20 Pacer, a light aircraft
- Pacer (train), a type of passenger railbus, used in the United Kingdom and the Middle East
- Pacer Stacktrain, a United States intermodal (container) freight transportation services company
- Pacer International, parent company of Pacer Stracktrain
- Sport
- Indiana Pacers, a basketball team in the United States
- Multi-stage fitness test, a personal endurance test involving running progressively faster: Progressive Aerobic Cardiovascular Endurance Run or "bleep test"
- Pacer, any horse that uses the pace gait, including:
- Narragansett Pacer
- Canadian Pacer
- A fast bowler in cricket
- Pacer (dinghy), a type of small sail powered racing boat, formerly called Puffin Pacer
- Pacer's Auto drag racing team, automobile competitors
- Safety car, used to maintain control in autosport racing
- Derny cycle, used to maintain control in cycle racing
- Pacemaker (running), athlete setting the pace for first section of a race
- Other
- Kramer Pacer, a series of kramer guitars made in the 1980s.
- The Pacer, a student newspaper circulated at the University of Tennessee
- Pacer, a brand of mechanical pencil
- Pacer (album), an album by The Amps
- Pacers (confection), brand of mint-flavored confection