Research to identify client factors that impact treatment outcome has found that deficits in metacognitive abilities and weaker therapeutic alliance are both associated with poorer treatment outcomes for schizophrenia. However, it is unknown if metacognition and therapeutic alliance are related in any way, in particular, if metacognitive abilities predict therapeutic alliance. This study explored whether differing capacities for mastery, a domain of metacognition that involves the ability to use knowledge about mental states to respond to psychological challenges, predicted client perceptions of therapeutic alliance assessed by the Working Alliance Inventory — Short Form (WAI-S). Participants were 63 adults with schizophrenia or schizoaffective disorder enrolled in a 6-month program of cognitive behavioral or supportive therapy, placed into a high, intermediate or minimal mastery group as measured by the Metacognitive Assessment Scale (MAS). Repeated measures ANOVA found group effects for the total WAI-S score, with the high and intermediate mastery groups having better alliance scores than the minimal mastery group. The group effects approached significance when neurocognition was controlled for. Results suggest that greater capacity for mastery predict stronger therapeutic alliance, but do not predict its development over time.