Both physical and relational aggression are characterised by the intent to harm another. Physical aggression includes direct behaviours such as hitting or kicking; relational aggression involves behaviours designed to damage relationships, such as excluding others, spreading rumours, and delivering threats and verbal abuse. This study extended research conducted in New Zealand (Page & Smith, 2012) to explore perceptions of Physical Aggression (PA) and Relational Aggression (RA) of Year 7 to 13 boys and girls (n = 443) and their teachers (n = 8) in the Cook Islands. It also investigated teachers' strategies used to manage aggression. Using a mixed-methods approach, results indicated that there was no gender difference in the perpetration of PA. Girls, however, were more likely to perpetrate and be targets of RA than were boys, but were more likely than boys to act in prosocial ways. Boys were more likely to be targets of PA. PA and RA were highly correlated for both genders. Finally, teachers' perceptions of RA and PA behaviours corresponded with those of the students, but their perceptions of effective strategies differed from those of the students. The findings are discussed in terms of developing strategies for building healthy relationships within Cook Islands' schools.