This research aimed to investigate primary school teachers’ attitudes towards students with mental health problems, specifically ADHD and anxiety. The goals of the research were: 1) to explore stigmatising attitudes in teachers. Did teachers report stigmatising attitudes towards students with ADHD and anxiety? 2) To explore gender-biased attitudes in relation to ADHD and anxiety. Did teachers show bias favouring ADHD/anxiety for one or other gender when information was held constant? Research was carried out using a behaviour analytic based implicit measure, the Implicit Relational Assessment Procedure (IRAP) and explicit self-report measures. Participants were working primary school teachers who taught students between 4-12 years of age. A total of 74 teachers took part in the research, with 66 providing data which could be used for analysis. Study 1 examined stigmatising attitudes towards students with ADHD or anxiety, specifically, did teachers display a negative bias towards students with ADHD/anxiety? A total of 36 primary school teachers took part, but only 30 provided useable data (n = 30). Participants ranged in age from 23-59 years old. Participants completed an IRAP and two explicit measures, the Days Mental Illness Stigma Scale (DMISS) and the Stigmatising Attitudes and Believability Questionnaire (SAB). Overall, results found that teachers did not display stigmatising attitudes towards students with ADHD or anxiety. Results from the IRAP found that teachers responded in a Disorder-Good-True manner and a Disorder-Bad-False manner, which suggests non-stigmatising implicit attitudes. Statistical analysis was carried out on the IRAP results using an ANOVA, the results of which indicated the presence of a significant IRAP effect on all trial types. Similar results were found on the explicit measures. Low scores on the DMISS and the SAB also indicated that teachers reported low stigmatising attitudes. Study 2 examined teachers’ gender bias in relation to students with ADHD and anxiety. Specifically it investigated whether teachers associated ADHD and anxiety with one gender or the other when all other information was held constant. A total of 38 primary school teachers took part in this study, with 36 providing useable data (n = 36). Participants ranged in age from 23-63 years old. As with Study 1, participants completed an IRAP and explicit measures. The explicit measures in this study comprised of vignettes and Likert-scale questionnaires. Overall results found that teachers did show a gender bias in relation to ADHD and anxiety. Results from the IRAP found that teachers showed a gender bias for both ADHD and anxiety. Teachers responded in an ADHD-Boy/Anxiety-Girl consistent manner, suggesting that they associate ADHD with boys and do not associate it with girls, and that they associate anxiety with girls, and do not associate it with boys. Again, significant IRAP effects were found for all trial types. Similar results were found in the explicit results. On the vignette measures the majority of teachers attributed ADHD type behaviours to boys and anxiety type behaviours to girls. This novel research adds to the small body of existing research in the area of attitudes towards children with mental health problems. The IRAP has not previously been used to examine these attitudes. Furthermore, teachers’ implicit attitudes towards children with mental health problems have not been previously investigated. Overall results are discussed in the context of previous research, recommendations for future research and practical implications.