Due to the uneven gender ratio of autism spectrum disorders (ASD), girls are rarely studied independently from boys. Research focusing on restricted and repetitive behaviors (RRBs) indicates that above the age of six girls have fewer and/or different RRBs than boys with ASD. In this study we investigated whether girls and boys with ASD demonstrated similar rates and types of RRBs in early childhood, using discrete observational coding from a video-taped play interaction. Twenty-nine girls with ASD were matched to 29 boys based on ASD severity. While boys in our sample demonstrated a greater frequency of RRBs, this was not significant and our findings indicate that girls and boys under five are more similar than dissimilar on this core deficit. However our data also revealed a trend toward gender-differential growth trajectories--a finding worthy of further investigation in larger samples.