ObjectivesTo conduct a systematic review on the translucency of bulk-fill (BF) composite materials, evaluating the factors influencing it and its clinical implications.Materials and MethodsA systematic search was performed on four databases (Embase, Medline/PubMed, Scopus, and Web of Science) for articles published until October 2, 2023. Search terms were: "translucency," "translucency parameter," "contrast," "contrast ratio," "bulk," "bulk-fill," "bulk fill," "composite," "resin," "resin based," "resin-based," "restoration," and "dental." In vitro studies, written in English language, investigating BF resin-based composites translucency were included. The risk of bias was performed with the RoBDEMAT tool.ResultsOf 590 screened articles, 13 were included in this review. They investigated 11 high-viscosity BF and 5 low viscosity ones. The limited number of the identified studies and the heterogeneity of the extracted data did not allow to conduct a meta-analysis.ConclusionsBF materials exhibit variability in translucency due to variations in experimental designs and the heterogeneous composition.Clinical SignificanceBFs may behave differently in masking the substrate or in blending capacity.