With the rapid development ofmaterials science and nanotechnology, stimuli-responsive drug delivery systems(DDS) for cancer therapy have drawn more and more attention. Mesoporous silica nanoparticles(MSNs) possess numerous advantages, such as large loading capacity, desirable biocompatibility, and various types of stimuli-responsiveness, which endowed them with significant roles in biomedical and related applications. Hybrid materials, particularly with MSNs as drug carriers and polymers as gatekeepers have emerged as promising DDS in recent years. In this review, we make an overview of such organic-inorganic hybrid materials for controlled drug release, with themain focus on the use of three types of polymer gating systems on the surfaces of MSNs, which include polymer brushes, polymers networks, and polymer coatings. On the basis of the types of connections, covalent or non-covalent, between these gatekeepers and drug carriers, we showcase the controlled drug release properties of these hybrid materials in response to a variety of external stimuli. The challenges and chances of hybrid nanocarriers constructed from MSNs and polymers are also discussed.