The study investigated adolescent students' perceptions of sleep duration and patterns, and the way they relate to emotional and behavioural difficulties. Five hundred and two students from public schools in Greece completed the Sleep Questionnaire and the Strengths and Difficulties Questionnaire (SDQ). It was demonstrated that consistency in sleep duration and quality in sleep patterns were associated with a reduction in adolescents' reports of emotional and behavioural difficulties. Sleep duration was similarly distributed across gender, while sleep patterns were gender-specific. Distinct differential effects of gender, sleep duration and patterns to adolescents' emotional and behavioural difficulties were also found. These findings and their implications for research and practice are discussed, within the scope of the biopsychosocial framework in education.