Adherence to treatment in psychiatric populations is notoriously low. In this randomized, controlled, proof-of-concept study, we sought to examine whether motivational interviewing (MI) could be used to enhance motivation for, adherence to, and benefit obtained from cognitive rehabilitation. Dual diagnosis MI, developed specifically for individuals with psychotic symptoms and disorganization, was further adapted to focus on cognitive impairments and their impact. Sixty-four outpatients diagnosed with schizophrenia spectrum disorders completed baseline assessments and were randomized to receive either the 2-session MI focused on cognitive functioning or a 2-session sham control interview focused on assessment and feedback about preferred learning styles. Next, all participants were given 4 weeks during which they could attend up to 10 sessions of a computer-based math training program, which served as a brief analog for a full course of cognitive rehabilitation. As hypothesized, MI condition was associated with greater increases in task-specific motivation along with greater training program session attendance. Moreover, postinterview motivation level predicted session attendance. There were no significant differences in improvement on a measure of cognitive training content, which may have been due to the abbreviated nature of the training. While the literature on the efficacy of MI for individuals with psychosis has been mixed, we speculate that our positive findings may have been influenced by the adaptations made to MI as well as the focus on a nonpharmacological intervention.