Drawing on attitude theories from social psychology, we conducted a survey of Australian pre-service (n = 327) and in-service (n = 127) teachers' attitudes about teaching children with attention-deficit/hyperactivity disorder (ADHD). This paper reports a content analysis of beliefs, affect and behaviours towards teaching children with ADHD and quantitative analyses pertaining to attitudinal ambivalence--that is, where a teacher may simultaneously report negative and positive evaluations of teaching children with ADHD. While on average, overall or global attitudes were mildly positive for both cohorts, considerable ambivalence about teaching children with ADHD was commonly experienced. Participants reported ambivalent beliefs, affect and behaviours, as well as ambivalence between these attitude components. Paradoxically, participants who knew more about ADHD and held stronger positive global attitudes about teaching children with ADHD reported less ambivalent behaviours towards these children, but reported more ambivalent beliefs. The implications for teachers' professional development and training are discussed.