In situations characterized by risk and uncertainty, people frequently base their decisions on beliefs concerning the likelihood of uncertain events. Such events can be as general as success in life or as specific as winning in a lottery, success in one's job or study, or even success with starting a new business. Beliefs and judgments about the likelihood of experiencing one's favored outcomes are referred to as outcome expectancies. They do not only influence individuals' decisions to seek or avoid specific situations, such as quitting school for the sake of starting a business, but also influence people's feelings experienced in situations not offering a choice. These feelings could, for example, be feelings of satisfaction or hope. Even if one cannot change anything and, thus, if no decision is to be made, unfavorable beliefs about a situation, and especially pessimistic beliefs about life in general, can cause stress. This, in turn, can harm an individual's health. Beliefs and judgments, therefore, exert substantial influence over individuals' decisions and, not to the least, their life in general.To better understand the formation of people's outcome expectancies, this thesis acknowledges that the likelihoods of different outcomes in one's life, at one's work place, or when starting a business are driven by different factors. Following previous research, three generic factors are distinguished: one's own abilities, other people, and chance. The thesis suggests a pattern how beliefs about these factors are associated with outcome expectancies. Beliefs about whether a factor helps or hinders favorable outcomes are referred to as efficacy beliefs. Beliefs about the degree to which these factors can influence one's outcomes are called control beliefs. Generalizing Bandura (1997), control beliefs are assumed to moderate the influence of efficacy beliefs on outcome expectancies. Efficacy and control beliefs therefore mirror the perceived structure and quality of processes driving the outcomes. Or, from a different perspective, the beliefs describe the different sources of risk associated with an outcome.Across three different contexts, life in general, work-related aspects of life, and entrepreneurship, propositions are tested and found to be supported by empirical data. Outcome expectancies generalized across one's life are positively associated with generalized efficacy beliefs. This association is found to be moderated by control beliefs. Similarly, for job satisfaction, and for its potential consequences emotional exhaustion and intentions to quit, data show that the association with self-efficacy and perceived instrumental social support (other-efficacy) is moderated by control beliefs. Consistent with Burger (1989), in both studies, life in general and work-related attitudes, a more internal than external locus of control can be associated with less optimistic outcome expectancies. Further, in two different datasets the relationship between entrepreneurial intentions and self-efficacy is moderated by control beliefs. The consistency of findings across different contexts suggests that the moderation effect represents a fundamental principle that applies in a wide variety of contexts. Moreover, the simplicity of the basic idea opens the path for a larger set of research questions, which may well reach beyond the concept of outcome expectancies.