Limited research has examined the well-being of international preschool teachers, while intervention targeting their well-being is even rarer. The objective of this study was to examine the effectiveness of a 2-month EASP (i.e., Early Advancement in Social-Emotional Health and Positivity) positive psychological intervention program based on the PROSPER--which stands for positivity, relationship, outcome, strength, purpose, engagement, and resilience-- framework on international preschool teachers' well-being in Hong Kong. Eighty-three teachers (M[subscript age] = 34.44 years, SD = 8.43, range = 19-53; female = 95.18%) were randomly assigned to the intervention (n = 44) and waitlist control groups (n = 39). Teachers completed survey measures of PROSPER well-being at baseline and after the intervention. The results of the multivariate regression analyses revealed that the intervention did not have significant overall effects on the PROSPER well-being, Wilks' lambda F(7, 56) = 1.28, p = 0.28, [eta]2 = 0.14. Yet, findings of univariate analyses suggested the intervention yielded significant medium effects on participants' relationship, outcome, strength and engagement (b = 0.26 to 0.45, 95% CI [0.04, 0.95], p = 0.02 to 0.03, [eta]2 = 0.07 to 0.08). The findings underscore the practical utility of the PROSPER framework in supporting international preschool teachers' well-being but, at the same time, highlight the need to further examine how cultural variations might implicate its effectiveness.