GPS Education Partners (GPSEd) is a community-based nonprofit organization and work-based learning intermediary offering a statewide manufacturing youth apprenticeship in Wisconsin. During their one to two years in the program, students meet high school graduation requirements, receive industry-specific and job-specific training, technical certifications, and Department of Workforce Development Youth Apprenticeship Certification. This report describes a research collaboration between GPSEd and American College Testing (ACT) that examined the relationships between ACT® WorkKeys® performance and outcomes for GPSEd students. Analyses revealed that WorkKeys scores correlated with academic outcomes like reading ability level and math course-taking patterns. WorkKeys scores and WorkKeys® National Career Readiness Certificate® (NCRC®) Levels were also related to Manufacturing Skill Standards Council (MSSC) Certified Production Technician (CPT) certificate attainment as well as attendance in GPSEd classes and apprenticeships. In all, the results suggest that WorkKeys provides useful signals of the foundational workplace skills required for success in a work-based learning program. Moreover, average WorkKeys scores increased significantly from junior to senior year, which is consistent with the notion that students can improve their foundational workplace skills in a work-based learning program.