Objectives: The project assessed the efficacy of a home-based intervention program for young children (n = 64, ages ranging from 3 to 6 years) with developmental delays in Vietnam. It was hypothesized that the children in the intervention group would show greater progress in adaptive behavior than the children in the control group. Methods: Assessment of the program efficacy was carried out by comparing children who received services for 6 months and those who did not. Children who were recognized as having developmental delays by teachers in kindergarten programs, and confirmed by trained evaluators based on the Vineland Adaptive Behavior Scale-II (VABS-II), were randomly assigned to intervention and control groups. Twenty student teachers were recruited from a teaching university and were provided with pre-program training and ongoing supervision. Results: The outcomes of the program were examined at 0, 3, and 6 months using the VABS-II. The intervention group improved significantly more than the control group in overall adaptive functioning and in the areas of communication, social skills, and motor skills. Conclusion: The project is one of only a few early intervention projects to apply randomized control trials in a low-middle-income country. The results demonstrate the feasibility of carrying out the intervention program using teachers with no prior experience of working with children with delays/disabilities, where professional resources are scarce for this population.