The problem of delay is a regular phenomenon in construction projects all around the world and the Malaysian building projects has no exclusion. The aim of this paper is to determine and rank the effects of delay in Malaysian building projects with respect to their Relative Importance Index. Literature review and questionnaire survey were used to gather data for this study. A thorough literature review was performed to identify the common effects of delays in building construction projects. A questionnaire was distributed among key project participants; contractors, clients and consultants, to rank the effects of delay in Malaysian building projects based on the perception of survey respondents. In total 300 questionnaires were distributed, as a result of 240 questionnaires were received. The collected data of questionnaire survey was analysed using statistical software SPSS. In total, 17 effects of the delays have been determined and findings from the survey revealed that time overrun, cost overrun, dispute, loss of profit, arbitration, claims, contract termination, litigation, poor quality of work, and total project abandonment were the main effects of delay in Malaysian building projects. The findings of this study might encourage construction stakeholders to focus on the issue of delays in building projects.