The main aim of this study was to develop a comprehensive scale to assess preschool teachers' self-efficacy to facilitate motor development activities. Scale validation was assessed through content, construct, and criterion validity, while reliability was determined through Cronbach's alpha and test-retest analyses. It was found that the content validity ratio of the items exceeded the threshold of 0.56 after content validity analysis. In addition, the content validity index for the scale was calculated to be a robust 0.903. A sample of 361 preschool teachers were then administered the scale. Exploratory factor analysis (EFA) was performed on the data obtained. The results of the EFA showed that the factor loading values ranged from 0.52 to 0.83. Following the EFA, a confirmatory factor analysis (CFA) was carried out, which resulted in a χ2/df value of 1.657. Other goodness of fit indices were as follows: GFI=0.90, TLI=0.94, IFI=0.95, CFI=0.95, RMSEA=0.043, SRMR=0.052. Overall, the scale explained 51.242% of the total variance. Consequently, the initial form was refined into a 27-item, 3-factor structure as a result of factor analysis. In terms of the criterion validity analysis, a significant positive relationship emerged between the scale and a comparable instrument measuring a related construct. Furthermore, regarding reliability analysis, the scale showed a high Cronbach's Alpha reliability coefficient of 0.88. The scale's test-retest reliability was confirmed with an intraclass correlation coefficient (ICC) of 0.77. In conclusion, this study provided a scale that can be deemed both valid and reliable for the assessment of the self-efficacy of preschool teachers in implementing motor development activities.