Social factors are an important contributor to the healthy aging of older adults. Previous research has investigated the effects of social strain and social support on older adults’ health separately and jointly. However, most previous work was limited to special populations or single time points. The current study examined indicators of social support and strain as predictors of six physical and mental health outcomes among a nationally representative sample of community-dwelling older adults in the United States, above and beyond sociodemographic factors. Changes in the outcomes were investigated with three waves of data spanning a ten-year period. Results from longitudinal multilevel models indicated that social support significantly predicted higher levels of self-rated health; lower levels of negative affect, loneliness, and unhappiness; and a slower decline in loneliness over time. Social strain significantly predicted higher levels of negative affect, loneliness, and unhappiness, as well as increased daily living difficulties over time.