High-quality education is essential to produce competent graduates in the field of dietetics. Assessment is a fundamental component of education and driver of learning, yet little is known about methods used to assess dietetics trainees. The objective of this review is to evaluate the practices and outcomes of methods used to assess dietetics trainees. A systematic review of the literature was undertaken. MEDLINE, the Cumulative Index to Nursing and Allied Health Literature Plus, Embase, and the Education Resources Information Center databases were searched from inception until May 31, 2017, using key terms that identified studies reporting practices for the assessment of dietetics trainees. Abstract and title screening was completed by three independent reviewers followed by full-text screening using the eligibility criteria. Quantitative and qualitative data were extracted. Study outcomes were evaluated using Miller’s Pyramid, Kirkpatrick’s Hierarchy, and the principles of programmatic assessment. Thirty-seven studies were identified. Assessments targeted all levels of Miller’s Pyramid with the does level being the most prevalent (n=23). Most studies focussed on evaluating Level 1 (participation) (n=16) and Level 2b (n=16) (knowledge and skills) of Kirkpatrick’s Hierarchy. Studies described single assessment instruments that focussed on instrument validity and reliability. Few studies considered a program of assessment or the role of expert judgment. Six themes were identified from qualitative data: (1) assessment for learning and professional development, (2) assessment requires motivated and skilled assessors, (3) trainees value authentic and global assessment, (4) assessment is evolving and context-sensitive, (5) poor assessment has negative implications, and (6) assessment evokes an emotional response. Studies focused on the development and evaluation of single quantitative-based instruments applied in isolation, with low-level outcomes sought. There is room to improve practices and design programs of assessment that combine quantitative and qualitative data for meaningful trainee feedback and credible assessment decisions. Comprehensive evaluation of assessment practices is required and must consider the contribution to improved health outcomes in all practice settings.