In this study, we investigate sleep quantity and quality and their association with anger-related reactions, symptoms of ADHD, depressive symptoms, physical health complaints, and life satisfaction in male prison inmates. Furthermore, we examine whether good sleep hygiene in the prison context (physical exercise during the day, switching the television off at night, limiting caffeine and cigarette consumption) is related to sleep quantity and quality. Forty-nine prison inmates (mean age = 39.37; SD = 13.95) completed questionnaires assessing sleep quality and quantity, sleep hygiene, and psychosocial and physical functioning. Short sleep duration (6 h or less) and poor sleep quality were related to higher levels of aggressiveness in aggression-provoking social situations and more physical health complaints. In addition, poor sleep quality was related to higher levels of rumination and more symptoms of ADHD. Daily caffeine consumption, a sleep hygiene variable, was related to shorter sleep duration. The results suggest that, among a sample of male prison inmates, adequate sleep duration and good sleep quality were associated with better psychosocial adjustment.