Recent research indicates that autism is under-recognized in girls and women. The current study investigated whether the gender-based assumptions of teaching staff impact the identification of autism. A survey was completed by 249 primary school teaching staff. After reading a vignette describing the behavior of a hypothetical child whose gender was randomly assigned, participants answered questions regarding possible reasons for the behavior described, including mental health and disability diagnoses and their confidence in their chosen answers. The gender of the described child was not found to have an impact on the likelihood of choosing autism as a potential diagnosis, suggesting that the participants did not make gender-based assumptions about autism characteristics. Higher qualified teachers were less confident in their answers than those with lower or no qualifications. Teachers may have more nuanced understandings of the complexities of autism than had been expected. Further research into the effect of gender on autism identification is needed.