Introduction: Assessment of ethics issues is an important part of health technology assessments (HTA). However, in terms of existence of quality assessment tools, ethics for HTA is methodologically underdeveloped in comparison to other areas of HTA, such as clinical or cost effectiveness. Objective: To methodologically advance ethics for HTA by: (1) proposing and elaborating Q-SEA, the first instrument for quality assessment of ethics analyses, and (2) applying Q-SEA to a sample systematic review of ethics for HTA, in order to illustrate and facilitate its use. Methods: To develop a list of items for the Q-SEA instrument, we systematically reviewed the literature on methodology in ethics for HTA, reviewed HTA organizations' websites, and solicited views from 32 experts in the field of ethics for HTA at two 2-day workshops. We subsequently refined Q-SEA through its application to an ethics analysis conducted for HTA. Results: Q-SEA instrument consists of two domains - the process domain and the output domain. The process domain consists of 5 elements: research question, literature search, inclusion/exclusion criteria, perspective, and ethics framework. The output domain consists of 5 elements: completeness, bias, implications, conceptual clarification, and conflicting values. Conclusion: Q-SEA is the first instrument for quality assessment of ethics analyses in HTA. Further refinements to the instrument to enhance its usability continue.