OBJECTIVE To understand fellowship program directors’ (FPDs) perspectives on facilitators and barriers to using entrustable professional activities (EPAs) in pediatric subspecialty training. METHODS We performed a qualitative study of FPDs, balancing subspecialty, program size, geographic region and current uses of EPAs. A study coordinator conducted 1-on-1 interviews using a semistructured approach to explore EPA use or nonuse and factors supporting or preventing their use. Investigators independently coded transcribed interviews using an inductive approach and the constant comparative method. Group discussion informed code structure development and refinement. Iterative data collection and analysis continued until theoretical sufficiency was achieved, yielding a thematic analysis. RESULTS Twenty-eight FPDs representing 11 pediatric subspecialties were interviewed, of whom 16 (57%) reported current EPA use. Five major themes emerged: (1) facilitators including the intuitive nature and simple wording of EPAs; (2) barriers such as workload burden and lack of a regulatory requirement; (2) variable knowledge and training surrounding EPAs, leading to differing levels of understanding; (3) limited current use of EPAs, even among self-reported users; and (4) complementary nature of EPAs and milestones. FPDs acknowledged the differing strengths of both EPAs and milestones but sought additional knowledge about the value added by EPAs for assessing trainees, including the impact on outcomes. CONCLUSIONS Identified themes can inform effective and meaningful EPA implementation strategies: Supporting and educating FPDs, ongoing assessment of the value of EPAs in training, and practical integration with current workflow. Generating additional data and engaging stakeholders is critical for successful implementation for the pediatric subspecialties.