Despite much progress in surface micromachining technology, friction, adhesion, and wear remain key issues, severely limiting the realization and reliability of many microelectromechanical systems (MEMS) devices. Recent researches on friction and wear in MEMS were reviewed and discussed in this paper. The surface effects influencing the frictional behavior in MEMS were discussed. The friction properties for micro and macro scales were compared. The methods to reduce the friction and wear in MEMS were also discussed.