Maithili (; Maithilī) is an Indo-Aryan language spoken in the Mithila region which is today mainly situated in northern and eastern Bihar of India and a few districts of the Nepal Terai. It is one of the largest languages in India and the second largest language in Nepal. Less commonly, it was written with a Maithili variant of Kaithi, a script used to transcribe other neighboring languages such as Bhojpuri, Magahi, and Awadhi.
In 2002, Maithili was included in the Eighth Schedule of the Indian Constitution, which allows it to be used in education, government, and other official contexts. It is recognized as one of the largest languages in India and is the second most widely used language in Nepal.
In 2007, Maithili was included in the Interim Constitution of Nepal 2063, Part 1, Section 5 as a Nepalese language.
In the past, Maithili was written primarily in Mithilakshar, but today it is written in the Devanagari script. Native speakers are referred to as Maithils.