Poor adherence to antiretroviral therapy (ART) has significant consequences for adolescents. Conditional economic incentives (CEI) is an approach that may help address this challenge. This study evaluated the safety and preliminary efficacy of a group-based CEI program for ART adherence improvement among a sample of adolescents living in Ghana. A total of 35 adolescents (mean age: 14.7 years) on ART, though still with detectable viral load, were recruited from an HIV clinic and divided into 5 balanced groups to participate in peer-led group-based CEI activities during routine clinic visits. Four assessments were conducted across four visits at baseline and 3-, 6-, and 9-month follow-up, respectively. Main outcomes were ART adherence and viral load. Linear mixed models and thematic analysis were used for data analyses. The majority (91.4%) of the participants attended all four intervention activities. Participants reported missing an average of 1.06, 0.50, 0.91, 0.55 doses of ART in the past 7 days at baseline, 3-, 6-, and 9-month assessments, respectively. Most viral loads were ≥5,000 copies/ml at both baseline (68.6%) and 6-month assessments (54.3%). The incentive was divided between individual compensation for attending clinic and completing the assessment ($5 each, $20 in total) and a group-based compensation valued at $40 that was distributed during the 9-month assessment according to average group attendance (A≥90%, B≥75%, C≥60%, D<60%) and group-average viral load (A=undetectable, B=50-499, C=500-4999, D≥5,000). The mean earnings for the participants was $46.70 (77.8% of possible earning). Qualitative data suggested that the CEI helped ART adherence through gaining personal and group benefits. Participants reported no teasing, bullying, or other undesirable behaviors from group members. They liked getting money for attending clinics/group meetings and obtaining undetectable viral load. We concluded that a group-based CEI was safe and had the potential to improve ART adherence and reduce viral load among Ghanaian adolescents.