A survey of 217 older adults assessed physical activity–related positive and negative social control and emotional and informational support, using structural equation modeling to investigate mediational effects of emotional responses and behavioral intentions on physical activity. There were significant indirect effects of social control and social support on intentions as mediated by positive, but not negative, emotional responses, and significant indirect effects of emotional responses on physical activity as mediated by intentions. These findings help to identify the cognitive and emotional pathways by which social control and social support may promote or detract from physical activity in later life.