Blockchain technology can potentially bring several positive changes in the marketing and advertising domain. This chapter explains the core features and advantages that the technology brings to marketing practices. The chapter examines how Blockchain can improve transparency, security, and trust in marketing and advertising transactions. Few real-world applications of Blockchain in digital advertising, customer data management, and loyalty programs are presented. The core message is that features of Blockchain, such as decentralization, transparency, and security, can fundamentally change how customers interact, manage data, and trust advertisers and brands, especially in the connected online digital world. By integrating Blockchain principles, organizations can enhance customer engagement, optimize marketing campaigns, and prioritize ethical practices. Customers have better control and ownership of data and can decide who, when, and for what timeframe they can access it.