Transitioning from frontend to backend development involves shifting focus from user interfaces to server-side logic, databases, and APIs. Start by learning backend languages like Node.js, Python, Ruby, or Java. Familiarize yourself with databases (SQL/NoSQL) and learn how to interact with them using ORMs or direct queries. Understanding server management, security practices, and RESTful API design is crucial. Practice by building full-stack applications, starting with simple backend features such as authentication, data handling, and API creation. Experiment with frameworks like Express (Node.js) or Django (Python).