The Self Regulatory Executive Function (S-REF) model implicates maladaptive metacognitive beliefs and processes in the predisposition and/or maintenance of positive psychotic symptoms. In the model, metacognitive beliefs guide cognitive and behavioural responses to cognitive experiences. This study tested for relationships between course of illness and levels of specific metacognitions in schizophrenia spectrum disorders. A large cohort of people with first episode psychosis (n = 578) recruited as part the OPUS trial (1998–2000) were tested. Information about course of illness (remitted, episodic or continually psychotic) and metacognitive belief ratings were collected. Data obtained from 367 participants revealed that levels of maladaptive metacognitive beliefs varied as a function of course of illness and distinguished between remitted patients and non-patients. Metacognitive beliefs explained 17 % additional variance displayed in course of illness in a multinomial regression analysis when controlling for other causal factors. In addition, beliefs concerning Need to Control thoughts (RR 1.13, 95 % CI 1.03–1.22, p < 0.01) predicted a continually psychotic course of illness. Elevations in metacognitive beliefs were associated with the severity and duration of psychotic symptoms, consistent with the S-REF model. Moreover, metacognition was a better predictor of course of illness than anxiety and depression. If these associations are shown to be causal, clinical interventions that modify metacognitive beliefs may also impact on positive symptoms and course of illness within schizophrenia.