The word Kaiser can mean:
- The German title meaning "Caesar" or "emperor"
- Several companies founded by Henry J. Kaiser:
- The Henry J. Kaiser Family Foundation (often "Kaiser Foundation")
- A type of bread roll
- A card game
- A Kaiser window is a window type in Digital Signal Processing
- Georg Kaiser (1878-1945), a German expressionist playwright
- Kaiser is a Brazilian beer
- Kaiser Chiefs are a britpop band
- A fictional ruler, see List of fictional rulers#Kaisers
- Kaizers Orchestra is a Norwegian rock band
Kaiser is also the root of the last name "Kaszer".