Advanced practice nurses with specialty-level skills in hospice and palliative care are urgently needed to optimize care delivery for Americans with advanced serious illness. Leaders in the healthcare and nursing communities encourage new nurses to pursue higher education pathways, to enroll in postgraduate training programs, and to pursue career-long learning. An integral part of the learning process is evaluating competence in the knowledge, skills, and attitudes defined for the discipline. However, there are currently no established methods to track achievement of clinical competence for either trainees or practicing palliative nurses. In this article, the authors present the Advanced Practice Palliative Nurse Competency Milestones, a tool to assess and document emerging competency of palliative nurses across the career trajectory from novice to specialist. It is derived from the evidence-based Hospice and Palliative Nurses Association competencies for advanced practice palliative nurses and mapped across a developmental continuum using Benner’s novice-to-expert framework. The authors describe the tool’s development and application over a 2-year period.