Foreign investment accounts for the largest proportion of project finance in the Cambodia's construction industry, where service providers are increasingly being tasked to be more productive. Low labour productivity has been identified as a major challenge of the country's construction industry. Addressing the constraints to labour productivity in the residential projects is crucial for improving the productivity of the sector. This study aimed to investigate the key constraints to labour productivity in residential projects which are specific to the socio-cultural and operational context of the Cambodia's residential sector. SPSS-based results showed four principal components extracted from 36 labour productivity inhibiting factors: Site management, external, workforce and resource factors. They accounted for 40 per cent, 26 per cent, 16 per cent and 10 per cent, respectively, of the variance that characterized poor labour productivity output in the sector. Forefront players who play active role in the project delivery process could ensure successful completion of projects to time, cost and quality targets by focusing efforts and resources on addressing issues relating to the most influential constraints identified under the four principal components as follows: providing good project leadership, ensuring better management of change orders, eliminating or minimizing defective work and ensuring adequate cash flow.