OBJECTIVE: We developed an implementation plan to integrate diagnostic testing for coronavirus disease 2019 (COVID-19) into a public school system. Implementation barriers were identified and strategies were mapped to overcome them. DESIGN: A COVID-19 diagnostic testing program leveraging a public-private partnership was developed for a public school system. SETTING: A suburban school district and a local hospital during the 2020-2021 academic year. METHODS: Using Consolidated Framework for Implementation Research (CFIR) constructs and evidenced-based implementation strategies, the program was designed as a "closed system" and was adapted based on stakeholder feedback. Implementation barriers and facilitators were identified and mapped to CFIR constructs to provide insights into factors influencing program adoption. RESULTS: Preimplementation stages of engagement, feasibility, and readiness planning were completed. The program did not progress to implementation due to multiple factors, including changes in school leadership (inner setting and process-level constructs), improved access to outside testing, and lack of an existing paradigm for in-school testing (external constructs). Limited support from key stakeholders and opinion leaders was also a barrier (process-level construct). CONCLUSIONS: Although this locally initiated program did not progress beyond the preimplementation stage, the processes developed and barriers identified may be useful to inform planning efforts in other testing programs within public school systems. Future programs may consider incorporating multiplex diagnostic testing for influenza in addition to COVID-19. With relaxation of infection control measures, the prevalence of other respiratory viruses will increase. Actionable results will be needed to inform decisions about closures and quarantines.