The purpose of this study was to examine sleep patterns in a large sample of infants and toddlers (ages birth to 36 months) in Korea, and to compare sleep patterns, sleep problems, sleep ecology, and parental behaviors to global sleep data on young children in both predominately Asian (P-A) and predominately Caucasian (P-C) countries/regions. We additionally examined parent and child demographic information, parental behaviors, and aspects of the sleep ecology as predictors of sleep patterns among infants and toddlers in Korea. Parents/caregivers of 1,036 Korean infants and toddlers completed an expanded, internet-based version of the brief infant sleep questionnaire. Consistent with other studies of sleep in early childhood, sleep/wake patterns became increasingly consolidated with older child age for the Korea sample. Compared to both P-A and P-C infants and toddlers, children in Korea had the latest bedtimes, shortest total sleep and daytime sleep durations, and the least frequent rates of napping. Even though half of parents perceive their children's sleep problematic, parental perceptions of severe child sleep problems were the lowest. Within Korea, breastfeeding and bottle-feeding at sleep resumption were associated with increased nocturnal awakenings. Evening television viewing was associated with later bedtimes, which may have implications for sleep hygiene recommendations in clinical practice. The current study provides important information about sleep/wake patterns, parental behaviors, and aspects of the sleep ecology for infants and toddlers for physicians to support healthy sleep in Korea.