The use of building information modeling (BIM) has been mandated by the Singapore government, but at the same time, non-value-adding (NVA) implementation practices are prevalent. However, little is known about the factors contributing to NVA BIM implementation practices from different stakeholders’ viewpoints. This study aims to identify the leading contributors to NVA BIM implementation activities in BIM-based building project delivery in Singapore, compare perceptions among stakeholders with different roles, firm sizes, and BIM implementation experience, and propose strategies for NVA implementation activity reduction. An extensive literature review and a pilot study were conducted to determine causes. The results of a questionnaire survey, statistical analyses, and four postsurvey interviews found that all 49 causes categorized by major stakeholders were critical. Among the most influential causes were “design models do not fit for intended downstream uses” (for architect/engineers) and “design changes are expensive once fabrication has commenced” (for manufacturer/supplier). The subgroup analysis indicated that contractors, especially those of small to medium size, perceived that the leading causes related to consultancy firms’ reluctance to enhance design-construction integration and consider incremental changes, whereas stakeholders without much BIM practical experience probably underestimated the difficulties of conducting value-adding BIM diffusion activities. This study extends the concept of NVA activities to BIM implementation and recommends management strategies for each project role to implement BIM-based collaborative practices. The findings enable practitioners to better understand BIM diffusion and reduce their NVA BIM implementation activities for enhanced construction productivity.