Abstract Objectives Implementation of advance care planning (ACP) in people with progressive multiple sclerosis (PwPMS) is limited. We aimed to involve users (PwPMS, significant others, and healthcare professionals involved in PwPMS care) in the evaluation and refinement of a booklet to be used during the ACP conversations. Methods This qualitative study consisted of cognitive interviews with PwPMS and significant others and a focus group with healthcare professionals from three Italian centers. We analyzed the interviews using the framework method and the focus group using thematic analysis. Results We interviewed 10 PwPMS (3 women; median age 54 years; median Expanded Disability Status Scale score 6.0) and three significant others (2 women; 2 spouses and one daughter). The analysis yielded three themes: booklet comprehensibility and clarity, content acceptability and emotional impact, and suggestions for improvement. Twelve healthcare professionals (7 neurologists, 3 psychologists, one nurse, and one physiotherapist) participated in the focus group, whose analysis identified two themes: booklet’s content importance and clarity and challenges to ACP implementation. Based on analysis results, we revised the booklet (text, layout, and pictures) and held a second-round interviews with two PwPMS and one significant other. The interviewees agreed on the revisions but reaffirmed their difficulty in dealing with the topic and the need for a physician when using the booklet. Conclusions Appraisal of the booklet was instrumental in improving its acceptability and understandability before using it in the ConCure-SM feasibility trial. Furthermore, our data reveal a lack of familiarity with ACP practice in the Italian context.