SummaryACTION Switzerland (NCT05232786) examined obesity‐related perceptions, attitudes, behaviours and potential barriers to treatment among people with obesity (PwO) and healthcare professionals (HCPs). In March/April 2022, adult PwO (body mass index ≥30 kg/m2, per self‐reported height/weight) and physicians/certified dietitians who manage PwO in Switzerland completed online surveys in a cross‐sectional design. Overall, 1002 PwO, 125 physicians and 25 dietitians completed the survey. Most physicians (97%) and dietitians (100%), but only 57% of PwO, recognized obesity as a chronic disease. Only 42% of PwO considered themselves to have obesity/extreme obesity, while 61% who had discussed weight with an HCP reported receiving an obesity diagnosis. Many PwO (76%) believed weight loss was entirely their responsibility; physicians were less likely than dietitians to agree it was completely their patients' responsibility (28% vs. 68%). Physicians and dietitians report primarily initiating conversations about weight when patients have obesity‐related comorbidities (85% and 64%); their top reasons for not discussing obesity were patients' perceived lack of motivation (76% and 60%) or interest (72% and 64%) in losing weight. In conclusion, some PwO are not aware that obesity is a chronic disease and incorrectly assume complete responsibility for weight loss. Improved communication between PwO and HCPs is required.