Paschim Champaran Lok Sabha constituency is one of the 40 Lok Sabha (parliamentary) constituencies in Bihar state in eastern India. This constituency came into existence in 2008, following delimitation of the parliamentary constituencies based on the recommendations of the Delimitation Commission of India constituted in 2002.This constituency is dominated by Muslims, Baniya, Brahmins and Kurmi & Kushwaha. It has 3,84,380 Muslim Voters, Brahmin & baniyas comprises 2 lakh voters each, Yadav and (Kurmi & Kushwaha) comprises 1.5 lakh voters each.

Presently, this constituency comprises six Vidhan Sabha segments, which are:^[1]

• Bettiah (Lok Sabha constituency)
• East Champaran district
• West Champaran district
• List of constituencies of the Lok Sabha
• Bettiah Raj