The main difference between TCP and UDP protocols lies in their approach to data transmission. TCP (Transmission Control Protocol) is connection-oriented, ensuring reliable communication by establishing a connection before data transfer, managing packet ordering, and retransmitting lost packets. This makes it suitable for applications where data integrity is critical, such as web browsing. In contrast, UDP (User Datagram Protocol) is connectionless and does not guarantee delivery or order, making it faster and more efficient for applications like streaming media and online gaming where speed is prioritized over reliability.