PurposeThis review paper aims to highlight the causes of delays (COD) and their interactions in construction projects, potentially aiding in timely completion and waste reduction through early anticipation.Design/methodology/approachForty-seven global literature were examined in detail to identify CODS and its interactions using the systematic literature review (SLR) method that utilised the PRISMA guidelines to ensure the studies reviewed were adequate to safeguard the robustness and comprehensiveness. Three-way analysis, such as Pareto, degree of centrality and loops, was undertaken to identify the critical Level 1,2 and 3 CODS that affect the Construction projects.FindingsThe research findings demonstrate that 65 CODs in eight categories affect construction projects. The CODs act in coherence rather than silos; the CLD displays complex interconnections of 44 factors obtained through the pairwise comparison of the 47 identified literature of the SLR. Through its systematic analysis of interaction loops, this research identified Ten level 1 critical CODs, two second-level critical CODs and 4 Third-level critical CODs. “Contractors' excessive workload/beyond potential/inadequate experience” emerged as the top COD that affects scheduling and project delay.Research limitations/implicationsThe study limitations include using only English articles and a restricted number of databases. However, the chosen databases were reputable and underwent thorough peer review processes. This study may have limitations due to the SLR, which means that factors affecting COD and interactions may vary by country, and future research is suggested for validation.Practical implicationsThis study identified interactions of construction delays that potentially support scheduling risk management during the early stage of the project and reduce waste to improve sustainability. The theoretical implications of SLR-based research include helping develop a framework that would potentially have all COD in the current scenario and aid future academic and industrial research factor-wise and country-wise in aiding sustainability. This will support and provide construction professionals and academia with knowledge of the COD related to factors and their interactions to be considered in the early assessment and management of future projects and improve sustainability.Originality/valueMost literature studies the factors or causes of construction delays that affect construction projects. The CODs primarily do not operate in silos but combine with other causes to enhance their influence on delays. Hence, it is of utmost importance to study the interactions of COD to enhance the knowledge in the construction field that would aid in schedule repair and, in turn, on-time project delivery. The study is the first related to COD and their interactions in construction projects in the digital era.