Bacterial infections cause severe secondary damage to wounds and hinder wound healing processes. We prepared magnesium oxide (MgO) nanoparticle-incorporated nanofibrous membranes by electrospinning and investigated their potential for wound dressing and fighting bacterial infection. MgO-Incorporated membranes possessed good elasticity and flexibility similar to native skin tissue and were hydrophilic, ensuring comfortable contact with wound beds. The cytocompatibility of membranes was dependent on the amounts of incorporated MgO nanoparticles: lower amounts promoted while higher amounts suppressed the proliferation of fibroblasts, endothelial cells, and macrophages. The antibacterial capacity of membranes was proportional to the amounts of incorporated MgO nanoparticles and they inhibited more than 98% E. coli, 90% S. aureus, and 94% S. epidermidis. MgO nanoparticle-incorporated membranes effectively suppressed bacterial infection and significantly promoted the healing processes of infected full-thickness wounds in a rat model. Subcutaneous implantation demonstrated that the incorporation of MgO nanoparticles into electrospun membranes elevated their bioactivity as evidenced by considerable cell infiltration into their dense nanofiber configuration and enhanced the remodeling of implanted membranes. This study highlights the potential of MgO-incorporated electrospun membranes in preventing bacterial infections of wounds.