Lichenology is the branch of mycology that studies the lichens, symbiotic organisms made up by the association of a microscopical alga with a filamentous fungus.

The taxonomy of lichens was first intensively investigated by the Swedish botanist Erik Acharius (1757-1819), who is therefore sometimes named the "father of lichenology". Acharius was a student of Carolus Linnaeus. Some of his more important works on the subject, which marked the beginning of lichenology as a discipline, are:
» Lichenographiae Suecia prodromus (1798)
» Methodus lichenum (1803)
» Lichenographia universalis (1810)
» Synopsis methodica lichenum (1814)

Later lichenologists include the American botanist Edward Tuckerman and the Russian evolutionary biologist Konstantin Merezhkovsky.