The concept of containerization in software deployment involves encapsulating applications and their dependencies into isolated units called containers. These containers can run consistently across various computing environments, including development, testing, and production. Containerization enhances portability, as containers can be easily moved and deployed on any system that supports the container runtime, such as Docker. This method also promotes efficient resource utilization and streamlined application scaling, making it a vital element in modern DevOps practices and microservices architectures.