Microlepidoptera (micromoths) is an artificial grouping of moth families, commonly known as the "smaller moths". These generally have wingspans of under 20 mm, so are harder to identify by external phenotypic markings than macrolepidoptera. They present some lifestyles that the larger Lepidoptera do not have, but this is not an identifying mark. Some hobbyists further divide this group into separate groups, such as leaf miners or rollers, stem or root borers, and then usually follow the more rigorous scientific taxonomy of lepidopterans. Efforts to stabilize the term have usually proven inadequate.

Moths are a group of insects that includes all members of the order Lepidoptera that are not butterflies. They were previously classified as suborder Heterocera, but the group is paraphyletic with respect to butterflies and neither subordinate taxon is used in modern classifications. Moths make up the vast majority of the order. There are approximately 160,000 species of moth, many of which have yet to be described. Most species of moth are nocturnal, although there are also crepuscular and diurnal species.