In this chapter, we will discuss the significant technological progress that has been made in the development of gene therapy strategies and the application of these strategies in specific therapeutic niches. More specifically, we aim to provide an overview of selected highlights from the past (preclinical development), current (first‐in‐man clinical trials), and future (remaining hurdles and regulatory aspects) of different gene therapy approaches. In these discussions, we will focus on gene therapy approaches using viral vectors because they are generally considered to be more efficacious and have yielded the most prominent clinical successes.