Causality orientations theory, a key sub-theory of self-determination theory, identifies three distinct causality orientations: autonomy, control, and impersonal orientation. The theory proposes generalized effects of the orientations on motivation and behavior. We meta-analyzed studies (k = 83) testing relations between causality orientations, forms of motivation from self-determination theory, and behavior. Pooled data were used to test a process model in which autonomous and controlled forms of motivation mediated relations between causality orientations and behavior. Results revealed that autonomy and control orientations were positively correlated with autonomous and controlled forms of motivation, respectively. Impersonal orientation was correlated negatively with autonomy orientation and autonomous forms of motivation, and positively with control orientation and controlled forms of motivation. Process model tests revealed total effects of autonomy orientation on behavior, comprising direct and indirect effects through autonomous motivation, and a positive direct effect of control orientation on behavior and a negative indirect effect through controlled motivation, resulting in a zero total effect. Analysis of age, gender, behavior type, study design, and study quality revealed few moderator effects on model relations. Findings support effects of autonomy orientation on motivation and behavior, and the processes involved, and identify constructs that could be targeted, or circumvented, in behavioral interventions.