BackgroundBehaviour parent training (BPT) is first‐line treatment for preschool attention deficit hyperactivity disorder (ADHD). BPT in a group format can be a cost‐ and time‐effective alternative in low and middle‐income countries (LMIC) settings with limited resources. We conducted a randomized controlled trial to compare the feasibility and efficacy of group BPT with individual BPT in improving ADHD severity in the preschool age group over 12 weeks.MethodsAfter approval by the ethical committee, the study was conducted in the child guidance clinic, JIPMER. Fifty‐six children aged 2.5 to 6 years diagnosed with ADHD according to DSM5 were recruited. Children with autism spectrum disorder and a social quotient less than 50 were excluded. Block randomization parallel design was done. Group interventions were delivered with 4–8 parents per group, focusing on psychoeducation, structuring of routine, attention enhancing tasks, behavioural parenting techniques, and TAU. ADHD severity was assessed using Conner's abbreviated behaviour rating scale at baseline, 4, 8, and 12 weeks. Parental stress was estimated by FISC‐MR adapted for ADHD. Statistical analysis included repeated measures ANOVA.ResultsSignificant improvement was noticed for both groups (F = 20.261, p < .001, ES (η2) = 0.539). Group intervention was not inferior to individual BPT in reducing ADHD severity (F = 0.860, p = .468, ES (η2) = 0.047). There was a statistically significant difference from baseline to 12 weeks of intervention in the reduction of parental stress (F = 20.80, p < .001, ES (η2) = 0.278) and enhancement of the coping strategies (F = 64.4, (p < .001), ES (η2) = 0.78). The intervention had high attendance and fidelity rates.ConclusionGroup BPT was promising in treating ADHD in low‐resource settings.