K-selected species (or competitor species) is a term to describe reproductive and survival patterns in organisms. Typically, K-selected species produce a few offspring, usually late in life, but these offspring have long generation times and are nurtured and protected by their parents until they reach reproductive age. These species succeed in competitive conditions when their population size is close to carrying capacity of their environment.

Examples of K-selected species are:

1. most large mammals, like elephants, whales, and humans
2. most seabirds and birds of prey
3. most sharks
4. large, long-living plants, like saguaro cactus, oak trees, and redwood trees
5. some tropical rain forest trees

The converse of K-selected is R-selected.