"Research Findings:" The influence of early childhood teachers' professional development on fundamental movement skills remains unknown in the literature. The purpose of the present study was to examine how early childhood teachers' professional development in physical education (PE) contributes to predicting children's fundamental movement skills. For this purpose, sixty early childhood teachers from Spain completed the Questionnaire Professional Development in Infant PE (QPD-IPE) to assess the teachers' professional development concerning PE. The Test of Gross Motor Development-2 was applied to evaluate the fundamental movement skills of their children (N = 300). Two separate hierarchical linear regressions were conducted to examine the effect of teachers' professional development in PE on locomotor and object control skills. The results illustrated that 18% of the variance in locomotor skills was predicted by minutes of PE, training and professional development, and external perception. Additionally, 22% of the variance in object control was predicted by minutes of PE, training and professional development, personal perspective, and years of teaching experience. Age and sex were controlled for in both models. "Practice or Policy:" Early teachers' professional development should receive attention to support preschoolers' fundamental movement skills.