An upward national trend in challenging behaviour amongst young children in Australian schools has prompted widespread concern and garnered frequent media scrutiny. Scholars have established that child-teacher relationships are central to understanding and mitigating challenging behaviour; however, exploration of teacher perceptions of children's challenging behaviour in the early years has been scant. This paper reports on findings drawn from a larger mixed-methods study of how teachers perceive, and respond to, young children's challenging behaviour. Survey data from 111 Western Australian teachers of Kindergarten to Year 2 showed that challenging behaviour is appraised contextually, and relational pedagogy is valued. The analysis revealed that teacher responses are affected by the complexity and frequency of challenging behaviours, teacher stress, inadequate support, and resource constraints. This paper highlights that teacher perceptions of young children's challenging behaviour offer a vital and unique lens through which to better understand and respond to challenging behaviour.