The theory of self-efficacy is that the more one believes in the efficacy of a specific activity, the more likely (motivated) one is to perform that activity. Most of the research into self-efficacy beliefs among older adults has been quantitative and has consistently supported the influence of those beliefs on behavior. However, it has not been established how efficacy beliefs actually influence motivation in older adults, or what sources of efficacy-enhancing information help strengthen those beliefs. The purpose of this study was to better understand the factors that influence the efficacy beliefs that motivate older adults in a rehabilitation program, and to uncover the relation between efficacy beliefs, motivation, and behavior (i.e., participation in rehabilitation activities). Seventy-seven older adults, 55 women and 22 men, in an inpatient geriatric rehabilitation program were interviewed. Through content analysis, 11 major themes were identified as factors that influence efficacy beliefs and motivate people to participate in rehabilitation: personal expectations, personality, role models, verbal encouragement, progress, past experiences, spirituality, physical sensations, individualized care, social supports, and goals. The findings support the theory of self-efficacy, and are best explained within a social cognitive theory framework.