This study aimed to develop and validate a temperament scale for Korean infants and toddlers aged 12~35 months, based on key and contemporary temperament theories reflecting their characteristics. An initial pool of 60 items was created across six factors, followed by exploratory factor analysis with data from 264 caregivers, This resulted in 42 items categorized into the following factors: activity level, cautiousness, effortful control, positive emotionality, negative emotionality and social sensitivity. Data from 776 participants were used for conducting confirmatory factor analyses, correlation analyses, mean comparisons, and reliability tests. Furthermore, criterion validity was investigated by examining the correlations with existing scales. The analysis confirmed the scale as a valid, reliable tool for toddlers. Lastly, the study summarized the scale’s attributes, applications, and limitations, and proposes directions for future research.