Purpose: To explore the selection, use, and reporting of theories, models, and frameworks (TMFs) in implementation studies that promoted healthy eating in center-based childcare. Data Source: We searched 11 databases for articles published between January 1990 and October 2018. We also conducted a hand search of studies and consulted subject matter experts. Study Inclusion and Exclusion Criteria: We included studies in center-based settings for preschoolers that addressed the development, delivery, or evaluation of interventions or implementation strategies related to healthy eating and related subjects and that explicitly used TMF. Exclusion criteria include not peer reviewed or abstracts and not in English, French, German, and Korean. Data Extraction: The first author extracted the data using extraction forms. A second reviewer verified data extraction. Data Synthesis: Direct content analysis and narrative synthesis. Results: We identified 8222 references. We retained 38 studies. Study designs included quasi-experimental, randomized controlled trials, surveys, case studies, and others. The criteria used most often for selecting TMFs were description of a change process (n = 12; 23%) or process guidance (n = 8; 15%). Theories, models, and frameworks used targeted different socioecological levels and purposes. The application of TMF constructs (e.g., factors, steps, outcomes) was reported 69% (n = 34) of times. Conclusion: Reliance on TMFs focused on individual-level, poor TMF selection, and application and reporting for the development of implementation strategies could limit TMF utility. (author abstract)