Overweight and obesity affect 45% of children and increases the risk for several negative health sequelae. Family-Based Behavioral Treatment (FBT) is the most efficacious treatment for child weight management and consists of nutrition and physical activity education, behavior change skills and parenting skills training. FBT is time and staff intensive and can include 20, 60-min separate groups for parents and children, as well as 20-min behavior coaching sessions to help problem solve barriers to implementing the skills learned and individualize the program. Guided self-help (GSH) therapies involve providing families a manual to review independently and brief coaching sessions by an interventionist to facilitate adherence. We developed a GSH version of FBT (gshFBT) which provides a manual to both parents and children and includes 14, 20-min coaching sessions over 6-months. The current study randomized 150 children (mean age = 10.1 years (SD = 1.38); mean BMI% = 97.3% (SD = 2.84); mean BMIz = 2.09 (SD = 0.40); 49% female; 43% Hispanic) and one of their parents (mean age = 41.8 years (SD = 6.52); mean BMI = 32.0 (SD = 7.24); 87.3% female; 43% Hispanic) to either a group-based FBT program or a gshFBT program. Assessments are conducted at baseline, post-treatment (6 months), 6-month follow-up (12 months) and 12-month follow-up (18 months). Primary outcomes are child weight change (BMIz) and cost effectiveness. Recruitment occurred between May 2017 and October 2021 and follow-up assessments are underway. Given the public health concern for children with obesity and the low level of access to FBT, gshFBT could prove extremely useful to provide intervention to a greater proportion of the population.