Actinomycetales, commonly referred to as Actinomycetes, is an order of bacteria in the class Actinobacteria. The suborders within Actinomycetales are Actinomycineae, Micrococcineae, Corynebacterineae, Micromonosporineae, Propionibacterineae, Pseudonocardineae, Streptomycineae, Streptosporangineae, Frankineae and Glycomycineae. Actinomycetales are filamentous gram positive bacteria with a high G+C content. They are best known as soil dwelling organisms, although various strains inhabit plants, animals and humans. They produce resistant spores which are often attached to aerial mycelium or hyphae

Actinomycetes are unsurpassed in their ability to produce many compounds that have pharmaceutically useful properties. In 1940 Selman Waksman discovered that the soil bacteria he was studying made actinomycin, a discovery which granted him a Nobel Prize. Since then hundreds of naturally occurring antibiotics have been discovered in these terrestrial microorganisms.