This study examined how different types of social interaction and competitive information in exergaming affect older adults’ motivation and attitude toward playing exergames. A 2 (time: pre- vs. posttest) × 3 (social interaction: play alone vs. play with peer vs. play with youth) × 2 (competition: competition informed vs. noncompetition informed) mixed experiment was conducted with 319 Singaporean older adults over 6 weeks through a three-way analysis of variance. Social interaction was found to significantly affect the changes of extrinsic motivation over time, while competitive information affected intrinsic motivation significantly. The results showed significant three-way interaction effects between time, social interaction, and competitive information on older adults’ extrinsic and intrinsic motivations. The changes of attitude over time were not affected by either social interaction or competitive information. The findings contribute to aging research and advance the knowledge of potential factors that promote the effective implementation of exergames for community older adults.