The construction industries of both developed and developing countries are dominated by construction small and medium enterprises (SMEs). The industry is project-based and requires knowledge workers for performance. Construction SMEs contribute significantly to employment generation, economic growth and prosperity, innovation diffusion, among others. They, however, are faced with poor productivity and performance, especially in the area of time, cost, quality and safety. This is hinged on their rigidity and inflexibility to the adoption of modern management techniques, amidst other external environmental constraints. Knowledge is a vital asset of organisations and knowledge management (KM) is a critical strategic and tactical management tool for improving organisations productivity, competitiveness and survival. This study aims to assess the factors limiting a full-scale implementation of effective KM practices among construction SMEs, especially on construction projects in the south-south region of Nigeria. This study leverages an electronic questionnaire and snowballs sampling technique to gather data from the SMEs' construction professional employees in the study. The collected data were analysed using factor analysis and the Mann-Whitney U test. The study found that technology-related barriers, cultural and management barriers, motivation and time barriers, awareness and communication barriers, and insecurity barriers, were the major cluster of factors limiting effective KM implementation by SMEs. Furthermore, no significant statistical difference in the perception of the small and medium-sized organisations was also found. It is recommended that adequate government and top management supports are needed to overcome the barriers and entrench KM practices as the key tactical and strategic tool for improving productivity and performance and ensuring the sustenance and survival of the construction SMEs.