Individuals living with spinal cord injury (SCI) have a high prevalence of obesity and unique barriers to healthy lifestyle. To examine barriers and facilitators to engagement and weight loss among SCI participants enrolled in the Group Lifestyle Balance Adapted for individuals with Impaired Mobility (GLB-AIM), a 12-month intensive lifestyle intervention. SCI participants = 31) enrolled in a wait-list, randomized controlled trial where all participants received intervention between August 2015 and February 2017. Analyses of pooled data occurred in 2020 to examine cross-sectional and prospective associations of hypothesized barriers and facilitators with (1) intervention engagement, comprised of attendance and self-monitoring, and (2) percent weight change from baseline to 12 months. We performed multivariable linear regression on variables associated with outcomes at < .05 in bivariate analyses and controlled for intervention group. Participants were middle-aged (mean age, 48.26 ± 11.01 years), equally male (50%) and female, White (80.7%), and unemployed (65.6%). In participants who completed baseline surveys ( = 30), dietary self-efficacy explained 26% of variance in engagement ( < .01); among the 12-month study completers ( = 22, 71.0%), relationship issues explained 23% of variance in engagement ( < .01). Money problems, health issues unrelated to SCI, lack of motivation, and experimental group explained 57% of variance in weight loss ( for model < .01), with lack of motivation uniquely explaining 24% of variance < .01). Improving engagement and weight loss for persons with SCI in the GLBAIM program may be achieved by addressing lack of motivation, relationship issues, and nutrition self-efficacy.