AbstractMass timber panel (MTP)-concrete composite floors are gaining increasing interest from builders and designers due to their optimized structural performance, light self-weight, and aesthetically exposed wood ceilings. Among various connecting techniques between timber and concrete, notched connections made by cutting grooves on timber and filling them with concrete are considered as one of the most structurally efficient and cost-saving connecting solutions. Numerous ways of making and reinforcing the notched connections, however, hinder the standardization and development of the design guidelines for this type of connection, which reduces the competitiveness of MTP-concrete composite floors. In this study, experiments were carried out to investigate the performance of MTP-concrete composite floors with different connection designs. Nine composite floor specimens with varying span, connection number, notch depth, concrete thickness, and loading direction were designed and tested under bending. The bending stiffness, load-carrying capacity, ductility, and failure mode of tested specimens were studied and discussed. Test results show that the connection number, notch depth, and concrete thickness affect the bending stiffness and strength of the floor positively, an increase in floor span impacts the floor performance negatively, whereas the effect of a limited number of self-tapping screws in the notch is negligible. The study also shows that MTP-concrete composite floors with high strength, high stiffness, and good ductility can be achieved through the optimized design of notched connections.