To identify and describe behavior change techniques (BCTs) used in rehabilitation for patients with rheumatic and musculoskeletal diseases (RMDs), according to their own perceptions. Further, to examine patients' descriptions of their capability, opportunity, motivation, and readiness for health behavior change. Patients were adults in need of specialized, multidisciplinary rehabilitation services due to inflammatory rheumatic disease, systemic connective tissue disease, or fibromyalgia / chronic widespread pain. Semi-structured interviews of 21 patients were analyzed with deductive qualitative content analysis applying three theoretical frameworks: the Behavior Change Technique Taxonomy, the transtheoretical model and stages of change, and the capability, opportunity, and motivation model of behavior. Forty-six BCTs aggregated within 14 BCT groups were identified used by either patients, healthcare professionals (HPs), or both. Goals and planning, feedback and monitoring, social support, shaping knowledge, repetition and substitution were most frequently used to facilitate behavior change. Twenty patients had reached the action stage and made specific lifestyle changes concerning more than half of their goals. Concerning other goals, 6 of these patients reported to be contemplating behavior change and 15 to be preparing for it. The rehabilitation process appeared to strengthen capability, opportunity, motivation, and the desired behaviors. Patient-reported barriers to behavior change were connected with restrictions in physical capability resulting from an unpredictable and fluctuating disease course, weakened motivation, and contextual factors, such as lack of access to healthcare support and training facilities, and high domestic care burden. The rehabilitation process seemed to strengthen individual and contextual prerequisites for behavior change and facilitate the use of required techniques and engagement in the desired behaviors. However, patients with RMDs may need prolonged support from HPs to integrate healthy lifestyle changes into everyday life. The findings can be used to optimize rehabilitation interventions and patients' persistent engagement in healthy behaviors.