AbstractUpon the completion of construction projects, quality assurance/quality control (QA/QC) must be conducted to guarantee the project quality complies with certain standards. The conventional QA/QC approach relies on manual measurements using conventional tools, which is inefficient and costly. Recently, terrestrial laser scanning (TLS) has been adopted for construction QA/QC due to its high speed and accuracy. However, research is still lacking to quantitatively analyze the potential time and cost benefits of TLS-based geometric QA/QC, and it is still not clear how and when a construction company should deploy TLS-based QA/QC. Hence, this study aims to provide a quantitative analysis of the time and cost benefits of TLS-based geometric QA/QC of buildings in comparison with the conventional QA/QC approach. First, a QA/QC checklist is determined based on relevant codes, and the processes and tasks of both conventional and TLS-based QA/QC approaches are identified. Second, a case study is conducted to collect the QA/QC time and cost for both approaches, and analyze the time and cost on both project and company levels. Third, the analysis results are further discussed considering potential technology advancements, fluctuations of cost items, changes of checklist items, and training needs. The results demonstrate that the TLS-based QA/QC approach is more efficient than the conventional QA/QC approach due to reduced data collection time. With regard to the cost, the TLS-based QA/QC approach with rented TLS is the most economical choice for a single project, and the TLS-based QA/QC approach with purchased TLS is the most economical choice for a company in the long term.