The aim of this study was to evaluate the validity and reliability of the Korean Tayside Children’s Sleep Questionnaire (K-TCSQ) for preschoolers. 203 parents of preschoolers aged 1.5-5 years old were surveyed, and the collected data were analyzed using SPSS 23.0 and AMOS 20. The results of this study were summarized as follows: First, exploratory factor analysis showed a 6-item 2-factor model(Initiating sleep(3 item) and Maintaining sleep(3 item)), confirmatory factor analysis was moderate. Second, correlation analysis showed that K-TCSQ’s total score and 2 factor scores were positively related to K-CBCL’s sleep problem, internal behavior problem, external behavior problem, and parenting stress. Third, internal consistencies of the K-TCSQ were acceptable. The significance of this study is that K-TCSQ was validated in Korean preschoolers, and it is expected that K-TCSQ can be used as an indicator of preemptive intervention by measuring sleep problems in preschoolers.