Specialist weight management services provide a treatment option for severe obesity. The objective of the study is to review the characteristics, impact and practice implications of specialist weight management services for adults in the UK. Systematic review: EMBASE, MEDLINE and PsycINFO were searched from January 2005 to March 2016 with supplementary searches. Adults with a body mass index of ≥40 kg m−2, or ≥35 kg m−2 with comorbidity or ≥30 kg m−2 with type 2 diabetes and any study of multicomponent interventions, in any UK or Ireland setting, delivered by a specialist multidisciplinary team are the inclusion criteria. Fourteen studies in a variety of settings were included: 1 randomized controlled trial, 3 controlled and 10 observational studies. Mean baseline body mass index and age ranged from 40 to 54 kg m−2 and from 40 to 58 years. The studies were heterogeneous making comparisons of service characteristics difficult. Multidisciplinary team composition and eligibility criteria varied; dropout rates were high (43–62%). Statistically significant reduction in mean body mass index over time ranged from −1.4 to −3.1 kg m−2 and mean weight changes ranged from −2.2 to −12.4 kg. Completers achieving at least 5%reduction of initial body weight ranged from 32 to 51%. There was evidence for improved outcomes in diabetics. Specialist weight management services can demonstrate clinically significant weight loss and have an important role in supporting adults to manage severe and often complex forms of obesity. This review highlights important variations in provision and strongly indicates the need for further research into effective approaches to support severely obese adults.