Recent research has shown an increase in academic dishonesty in different educational systems and levels, and negative effects on the academic institution, society and the students themselves. In order to describe the differential perception of academic dishonesty by Spanish secondary school and university students, and to study its consequences on psychological well-being, comparisons between two groups of students from secondary education and university were carried out, using measures of the perception and execution by others of dishonest behaviour, as well as psychological well-being and satisfaction with life and learning. University students revealed greater laxity of conscience, considering dishonest behaviour to be less serious and more common than secondary school students, and indulging in more dishonest behaviour themselves. They also showed greater spiritual, personal, community and environmental well-being, and greater satisfaction with learning. However, transcendental spiritual well-being was greater in the group of secondary education students. Academic dishonesty was associated with satisfaction with learning in both groups, and with satisfaction with life in secondary education. Its link with measures of spiritual well-being was greater in the group of secondary education students, being linked to transcendental well-being only in the group of university students. No gender differences were observed in any of the variables.