Background: Kindergartens and other preschool facilities provide preschool children with an important setting for social interactions. Social interaction supports the development of social skills in children and is associated with better subsequent performance in arithmetic. Objective: This study reviewed the literature to; (a) identify targets treated as social interactions and examine measurable social interactions in preschool education and care settings, (b) to organize the methods used to assess social interactions and explore feasible methods for implementation in preschool education and care settings. Methods: The literature review was based on English-language articles published in peer-reviewed journals. Twenty-six such articles were selected for review after meeting all the selection criteria. For each article, six items were analyzed: (a) size and age of the participants in each sample, (b) setting, (c) study period and the number of data retrieval sessions, (d) measurement approach (type of measurement, instruments used, recording method), (e) social interactions measured, and (f) evaluators. Results: A number of indicators of social interaction were featured in the research, including the target children's behavior directed toward others, their participation in activities involving two or more participants, and their expressions. Several methods were used to record these observations, including interval recordings, fieldnotes, and existing forms/techniques. Conclusions: This study reveals that it is important to consider indicators other than utterances and conversation, such as behaviors, facial expressions, and forms of activity. And it is necessary to consider methods that can be implemented by teachers when they routinely collect social interaction data.