Online volunteering has emerged as a prominent phenomenon in the digital age, enabling individuals to contribute their time, skills, and expertise remotely through online platforms. This chapter provides an overview of online volunteering from an operations management perspective. It begins by defining online volunteering and highlighting its significance in contemporary society due to its growing impact. The chapter explores the distinctive features of online volunteering compared to traditional, offline volunteering and elucidates how online volunteering is implemented in practice. Subsequently, it considers the challenges faced by volunteers, nonprofit organizations, and online volunteering platforms, illustrated through two real-world case studies. The chapter then examines how the existing literature on operations management has addressed some of these challenges. Finally, it proposes potential directions for future research to deepen our understanding of online volunteering. By exploring these themes, this chapter serves as a stepping stone for scholars, practitioners, and nonprofit organizations interested in advancing the theory and practice of online volunteering.