Although the academic gains associated with acceleration and peer ability grouping are well documented, resistance to their use for gifted students continues because of concerns that such practices will cause social or emotional harm to students. Results from the broad research indicate that grade skipping, early school entrance, and early admission to college have socioaffective benefits for gifted students who are selected on the basis of demonstrated academic, social, and emotional maturity, but may be harmful to unselected students who are arbitrarily accelerated on the basis of IQ, achievement, or social maturity. There is little research on the socioaffective effects of peer ability grouping. The limited evidence indicates strong benefits for highly gifted students and possibly for some minority or disadvantaged gifted students. Robust evidence does not exist to support the idea that heterogeneous classroom grouping per se significantly increases the risk for adjustment problems among moderately gifted students. Recommendations for best practice based on the available evidence are presented. (Contains 2 tables.)