Competitive interactions shape the evolution of organisms. However, often it is not clear whether competition is the driving force behind the patterns observed. The recent use of experimental evolution in competitive environments can help establish such causality. Unfortunately, this literature is scattered, as competition for food, mates, and hosts are subject areas that belong to different research fields. Here, we group these bodies of literature, extract common processes and patterns concerning the role of competition in shaping evolutionary trajectories, and suggest perspectives stemming from an integrative view of competition across these research fields. This review reinstates the power of experimental evolution in addressing the evolutionary consequences of competition, but highlights potential pitfalls in the design of such experiments. Organisms compete for several resource types, the most studied being food, mates, and hosts. The study of each resource type belongs to different research fields, each with its own idiosyncrasies, including distinct vocabulary. There are similarities in patterns and processes across diverse research fields that implicitly or explicitly study competition, as in all cases, individuals are competing for the use of a limiting resource. The use of experimental evolution as methodology allows for a complete understanding of the reciprocal effects of competition on evolution. Experimental evolution can be transversally applied to studies of competition across diverse research fields, in view of establishing a common integrative framework. An integrative view of competitive interactions creates new predictions and clarifies patterns observed.