Quorum quenching (QQ) has been recognized as an innovative approach for biofouling control in membrane bioreactors (MBRs). Recently, QQ bacteria entrapping beads (QQ-beads) have been developed and verified to have excellent anti-biofouling potential in a pilot-scale MBR with flat-sheet membrane modules. In this study, considering the dense structure of hollow fiber (HF) bundles into which QQ-beads can hardly penetrate, QQ bacteria entrapping sheets (QQ-sheets) were developed as a new shape of QQ-media suitable for MBRs with HF modules. In a lab-scale MBR, QQ-sheets with a thickness of 0.5 mm exhibited a greater physical washing effect than did QQ-beads with a diameter of 3.5 mm because the former collided with membrane surfaces at the inner as well as the outer part of HF bundles, whereas the latter only made contact with the outer part. Moreover, QQ-sheets showed 2.5-fold greater biological QQ activity than did QQ-beads due to their greater total surface area at a fixed volume of QQ-media. These results suggest high potential for QQ-sheets to be used in MBRs with HF modules.