Background <p>The improvement of health-related quality of life (QoL) after metabolic and bariatric surgery (MBS) is an indicator of success. Due to alterations in the upper gastrointestinal (GI) tract after MBS, important changes occur in the GIQoL. Consequently, patients develop new GI symptoms that affect their lifestyle and interpersonal relationships (IIRR). Therefore, questionnaires specifically assessing GIQoL are necessary. This work aimed to design and validate a GIQoL.</p> Methods <p>The questionnaire development process was divided into four phases. Phase I–II consisted of initial items generation through a literature review, expert consensus (Delphi study), and patient discussion groups (14 patients who underwent to BS). In Phase III, the results were analyzed qualitatively and unified, obtaining the “Questionnaire version 0.” Currently, phase IV is in process, and it will consist of analysis its psychometric properties for its final validation.</p> Results <p>After literature review, no GIQoL questionnaires were found in this type of patient. The Delphi study consensus was reached on 8 of 15 proposed items. Most patients recognized a general deterioration of their GIQoL compared to the period prior to surgery. The final questionnaire has 13 questions, covering 3 dimensions: GI and psychological symptomatology, the influence of the eating habits on daily life, and impact of BS on IIRR.</p> Conclusions <p>This article describes the process of developing a specific GIQoL questionnaire, which will be completed once we have carried out its psychometric analysis. This questionnaire fills a critical gap in the current assessment of GIQoL after MBS, offering a validated and specific tool that can be integrated into clinical practice.</p>