<p>The goal complex model (Elliot and Thrash in Educational Psychol Rev 13:139–156) offers a novel view of achievement goals. It proposes that people can pursue an achievement goal (i.e., performance or mastery) for many reasons and that the goal’s effects depend partly on those underlying reasons. Over two dozen studies support this premise. However, to date, nearly all of them have only tested autonomous reasons vs. controlling reasons, two broad opposing goal-pursuit reasons borrowed from self-determination theory. That approach ignores that many people pursue an achievement goal for multiple reasons, not just one. Studies must now examine whether the number and diversity of goal pursuit reasons matters too. The present research does so by applying goal systems theory (Kruglanski et al.in Adv Motivation Sci, 2:69–98) to goal complexes. It tested two novel hypotheses: first, that people are more committed to an achievement goal when they have more reasons for pursuing it, and second, that they perceive performance goals and mastery goals as more compatible when their reasons for pursuing the two goals converge. Two survey studies with different populations—university students (<i>N</i> = 335) in Study 1, working adults (<i>N</i> = 212) in Study 2—confirmed both hypotheses. Each also showed that most people pursue both goals, that they consider the two goals compatible, and that pursuing both elevated their commitment to each goal. The findings offer new insights into goal complexes as well as the long-standing debate about whether performance and mastery goals can work well together.</p>