An electronic organ is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally, it was designed to imitate the sound of pipe organs, theatre organs, band sounds, or orchestral sounds. Today, it has developed into three or more types of instruments:

• Hammond-style organs used in popular music genres;
• digital church organs, which imitate pipe organs and are used primarily in churches;
• various other types including combo organs, home organs, and software organs.