Lucas "Luke" Purugganan Bersamin (born October 18, 1949) is a Filipino lawyer and jurist who currently serves as the 40th Executive Secretary of the Philippines.

He was then named a fellow at the Commonwealth Judicial Education Institute in Dalhousie University in Halifax, Nova Scotia, Canada.

President Rodrigo Duterte appointed Bersamin as the new chief justice on November 26, 2018, succeeding Teresita Leonardo-De Castro.

[9][10][11] On February 6, 2020, Bersamin was appointed by Duterte to be the chairperson of the Government Service Insurance System (GSIS) and a member of the agency's board of trustees.

[13] Bersamin is married to the former Aurora A. Bagares, a business proprietress, with whom he has three children: Pia Cristina, Luis Isidro, and Lucas Riel Jr.