Many firms have outsourced most of their outsourcing tasks to third parties in recent years. However, traditional outsourcing procedures have challenges like centralization, data security, complex payment systems, time-consuming and costly dispute resolution methods, and the need for more trusted real-time tracking and monitoring systems. This chapter delves into the paradigm shift from traditional outsourcing methods to new trustless and decentralized Blockchain-based outsourcing methods. Blockchain, with its core principles of decentralization, immutability, and transparency, is a primary candidate to solve the challenges of traditional outsourcing methods. The main objective of this chapter is to explore the benefits of integrating Blockchain in outsourcing of supply chain operations and management science methods. Moreover, the chapter also investigates some real-time industrial use cases and research works. The chapter discusses the challenges in integrating Blockchain, potential solutions, and future research directions.