Maithili is an Indo-Aryan language spoken in parts of India and Nepal. It is native to the Mithila region, which encompasses parts of the Indian states of Bihar and Jharkhand as well as the Nepalese Koshi and Madhesh Provinces. It is one of the 22 official languages of India. It is the second most commonly spoken language of Nepal. It is also one of the fourteen provincial official languages of Nepal.

The Indo-Aryan languages are a branch of the Indo-Iranian languages in the Indo-European language family. As of the early 21st century, they have more than 800 million speakers, primarily concentrated in Bangladesh, India, Pakistan, Sri Lanka, Maldives and Nepal. Moreover, apart from the Indian subcontinent, large immigrant and expatriate Indo-Aryan–speaking communities live in Northwestern Europe, Western Asia, North America, the Caribbean, Southeast Africa, Polynesia and Australia, along with several million speakers of Romani languages primarily concentrated in Southeastern Europe. There are over 200 known Indo-Aryan languages.