Research suggests that spatial ability plays a significant role in science, technology, mathematics, and engineering (STEM). Crucially, gender differences in favor of males are observable in STEM enrollment and success and spatial cognition. There is ample evidence regarding the influence of stereotyping in this context. Moreover, stereotypes about spatial ability have been demonstrated in children as young as ten years of age. However, there are no scientific studies investigating the presence and potential influence of such stereotypes on spatial ability at even younger ages. The aim of the current study is to illuminate parts of the uncertainty regarding gender stereotypes related to spatial ability in early childhood and their potential relation to mental rotation performance. To this end, approximately 120 five and six year old children (data collection ongoing) will complete an Implicit Association Test, a questionnaire relating to stereotypes about spatial ability, and a chronometric mental rotation task. Additonally, parents will provide information regarding their socioeconomic status (SES). SES will serve as a covariate in this study. We hypothesize that children will hold implicit and explicit gender stereotypes concerning spatial toys and activities, linking them to boys rather than girls. We also expect older children to demonstrate stronger associations in this regard, and boys to demonstrate stronger associations in this regard compared to girls. Lastly, we expect that stereotype endorsement will relate to mental rotation performance such that a stereotype suggesting greater ability of the own gender will be linked with better performance. This study was preregistered on osf.io.