This article offers a systematic review of studies of personality and the dimensions of temperament and character, personality pathology, and personality disorders (PDs) in adults with autism spectrum disorder (ASD). Fifteen studies met the inclusion criteria for the review, from which seven studies were meta-analyzed. Results indicate that ASD is significantly and systematically associated with an introvert, rigid, passive-dependent temperament with low novelty seeking, high harm avoidance, low reward dependence and high persistence, and with an immature and poorly developed character with low self-directedness, low cooperativeness, and high self-transcendence. The review further finds a positive correlation between ASD (severity) and neuroticism and a negative correlation between ASD (severity) and extraversion, openness to experience, agreeableness, and conscientiousness. It also finds a positive correlation with paranoid, schizoid, schizotypal, avoidant, and obsessive-compulsive PDs. However, the far from perfect associations indicate there is considerable variation between people with ASD in their personality and personality pathology. In order to obtain a comprehensive picture of an individual with ASD and to implement the most effective intervention plans for and therapeutic relationship with adults with ASD, temperament, character, and comorbid personality pathology and PDs should be considered.