<b><i>Introduction:</i></b> Obesity is a global health challenge, and pharmacologic options are emerging. Once daily subcutaneous administration of 3 mg liraglutide, a glucagon like peptide-1 analogue, has been shown to induce weight loss in clinical trials, but real-world effectiveness data are scarce. <b><i>Methods:</i></b> It is a single-centre retrospective cohort study of patients who were prescribed liraglutide on top of lifestyle adaptations after multidisciplinary evaluation. In Belgium, liraglutide is only indicated for weight management if the BMI is &#x3e;30 kg/m² or ≥27 kg/m² with comorbidities such as dysglycaemia, dyslipidaemia, hypertension, or obstructive sleep apnoea. No indication is covered by the compulsory health care insurance. Liraglutide was started at 0.6 mg/day and uptitrated weekly until 3 mg/day or the maximum tolerated dose. Treatment status and body weight were evaluated at the 4-month routine visit. <b><i>Results:</i></b> Between June 2016 and January 2020, liraglutide was prescribed to 115 patients (77% female), with a median age of 47 (IQR 37.7–54.0) years, a median body weight of 98.4 (IQR 90.0–112.2) kg, a BMI of 34.8 (IQR 32.2–37.4) kg/m², and an HbA1c level of 5.6%. Five (4%) patients did not actually initiate treatment, 9 (8%) stopped treatment, and 8 (7%) were lost to follow-up. At the 4-month visit, the median body weight had decreased significantly by 9.2% to 90.8 (IQR 82.0–103.5) kg (<i>p</i> &#x3c; 0.001). Patients using 3.0 mg/day (<i>n</i> = 60) had lost 8.0 (IQR 5.8–10.4) kg. The weight loss was similar (<i>p</i> = 0.9622) in patients that used a lower daily dose because of intolerance: 7.4 (IQR 6.2–9.6) kg for 1.2 mg (<i>n</i> = 3), 7.8 (IQR 4.1–7.8) kg for 1.8 mg (<i>n</i> = 16), and 9.0 (IQR 4.8–10.7) kg for 2.4 mg/day (<i>n</i> = 14). Weight loss was minimal if liraglutide treatment was not started or stopped prematurely (median 3.0 [IQR 0.3–4.8] kg, <i>p</i> &#x3c; 0.001, vs. on treatment). Further analysis showed an additional weight reduction of 1.8 kg in the patients that had started metformin &#x3c;3 months before the start of liraglutide (<i>p</i> &#x3c; 0.001). The main reasons for liraglutide discontinuation were gastrointestinal complaints (<i>n</i> = 5/9) and drug cost (<i>n</i> = 2/9). <b><i>Conclusion:</i></b> In this selected group of patients, the majority complied with liraglutide treatment over the initial 4-month period and achieved a significant weight loss, irrespective of the maximally tolerated maintenance dose. Addition of metformin induced a small but significant additional weight loss.