Background: Adolescents with mild-to-borderline intellectual disability face peer resistance challenges, risking harmful or dangerous situations. Method: We designed a peer resistance group intervention at school for adolescents with mild-to-borderline intellectual disability, tested its feasibility (N = 4, M[subscript age] = 14.1, M[subscript IQ] = 78.8), adapted it, and tested it again (N = 6, M[subscript age] = 15.0, M[subscript IQ] = 72.8). Results: Study 1 demonstrated feasibility in recruitment, resources, and potential benefits on the distal outcome risk taking. However, attendance, obtained knowledge, and potential benefits on peer resistance, peer problems, and prosocial behaviour were suboptimal. Consequently, study 2 contained more learning by doing and individual lessons, resulting in higher attendance and greater personalization. While potential benefits on improved peer resistance measures were not observed, risk taking improved. Conclusions: Despite finding no potential benefits on peer resistance, running a peer resistance intervention for adolescents with mild-to-borderline intellectual disability at school is considered feasible.