Khair Assembly constituency (Hindi: खैर विधान सभा निर्वाचन क्षेत्र) is one of the 403 constituencies of the Uttar Pradesh Legislative Assembly, India. It is a part of the Aligarh district and one of the five assembly constituencies in the Aligarh (Lok Sabha constituency). First election in this assembly constituency was held in 1951 after the "DPACO (1951)" (delimitation order) was passed in 1951. After the "Delimitation of Parliamentary and Assembly Constituencies Order" was passed in 2008, the constituency was assigned identification number 71.