Adolescent versions of the Empathy Quotient (EQ) and Systemizing Quotient (SQ) were developed and administered to n = 1,030 parents of typically developing adolescents, aged 12–16 years. Both measures showed good test–retest reliability and high internal consistency. Girls scored significantly higher on the EQ, and boys scored significantly higher on the SQ. A sample of adolescents with Autism Spectrum Conditions (ASC) (n = 213) scored significantly lower on the EQ, and significantly higher on the SQ, compared to typical boys. Similar patterns of sex differences and cognitive brain types are observed in children, adolescents and adults, suggesting from cross-sectional studies that the behaviours measured by age-appropriate versions of the EQ and SQ are stable across time. Longitudinal studies would be useful to test this stability in the future. Finally, relative to typical sex differences, individuals with ASC, regardless of age, on average exhibit a ‘hyper-masculinized’ profile.