The study was to understand how online video consumption patterns affect preschoolers’ selfregulation. A questionnaire was developed based on other scales in previous studies. The survey was conducted from June 3 to June 24, 2019, with 263 mothers of 3, 4, 5-year-old children enrolled in preschool and day care centers in South Korea. The analysis of the collected data was performed on SPSS 21.0, calculating frequencies and percentages and applying the t-test and one-way ANOVA. A considerable proportion of the respondents (41.4%) reported they permitted their child to use the online video platform before 24 months of age. Most children watched online video following the rules that their parents established (75.7%). Significant differences were found in children’s self-regulation depending on the presence or absence of the rules at home, the amount of screen time limit, when to watch during the day or during weekdays. This study provides empirical evidence to set preliminary guidelines for the optimal viewing conditions for preschoolers to avoid online video addiction.