Caregivers are increasingly recognised as significant in providing naturalistic interventions for children with autism spectrum disorder in high-income countries and low- and middle-income countries including Sri Lanka. It is imperative to assess the impact of programmes targeting desired parenting skills within cultural boundaries. A preliminary study evaluated the effectiveness of a play-based parent coaching programme by assessing caregiver interaction skills. A mixed-method approach included a prospective pre-post interventional study. A caregiver skills assessment checklist was designed by adapting a freely available tool to assess caregiver-child interactions following a 3-h parent coaching programme. Pre-/post-training 10-min video recordings were obtained for each child-caregiver dyad 2 weeks apart. Thirty mothers (25-55 years) participated. Mean scores improved significantly in all caregivers (p < 0.005) for special emotional (8.80-22.83), cognitive (4.63-14.13) and language (5.53-12.97) domains. Higher education level and older age of caregivers positively associated with the skill acquisition. Qualitative data revealed caregiver satisfaction of detailed workshops. Promising short-term outcomes demonstrated the potential role of parents as partners in autism spectrum disorder management in low- and middle-income countries. Longer-term outcomes on larger groups of children and caregivers need exploration.