Context: School closures in California due to COVID-19 have had a negative impact on the learning advancement and social development of K-12 students. Since March 2020, the achievement gap has grown between high-income and low-income students and between White students and students of color. Program: In November 2020, a team from the California Department of Public Health, University of California, San Francisco, and University of California, Los Angeles, developed the School Specialist training for local health department and state employee redirected staff to the COVID-19 response to equip them to support schools as they reopen. Implementation: A pilot of the virtual School Specialist training was carried out in December 2020, which informed subsequent biweekly half-day virtual trainings. The training consisted of lectures from experts and skill development activities led by trained facilitators. Evaluation: The objectives of the evaluation of the training were to understand whether (1) knowledge of key concepts improved from pre- to posttraining; (2) confidence in skills central to the role of a School Specialist improved from pre- to posttraining; and (3) course learners who were activated to work as School Specialists felt the training adequately prepared them for the role. The School Specialist training team sent pre- and posttraining surveys to learners between February 8 and May 18, 2021. Of the 262 learners who responded, a significant improvement was seen in knowledge, with a mean score increase of 15.6%. Significant improvement was also observed for confidence, with a 20.1% score improvement seen posttraining. Discussion: Overall, the School Specialist training was shown to be effective in increasing knowledge and confidence in preparation for School Specialist deployment. Adequate training and partnerships for local health department and school staff are critical to keep K-12 students safe and to reduce the learning achievement gap during the ongoing COVID-19 pandemic.