Nabil Alfad Tan (born April 22, 1955) is a Filipino politician and lawyer serving as a member of the Bangsamoro Parliament since 2019, where he currently serves as a deputy speaker since 2021.
Tan is a native Tausug from Sulu. He attended elementary school at the Philippine Muslim College, and high school at the Notre Dame of Jolo College. He earned his Bachelor of Arts in political science and Bachelor of Laws degrees at the University of the East in Manila, and later pursued a masters degree in government management at the Pamantasan ng Lungsod ng Maynila. He passed the bar examination in March 1981.
Tan initially served as the Chief of the Legislative Staff of the national House of Representatives from 1988 to 1989 in the 8th Congress, prior to beginning his political career in 1990, when he was elected to the ARMM Regional Legislative Assembly as a member for the first district of Sulu.
Near the end of his term as an assemblyman, Tan was elected Regional Vice Governor of the former Autonomous Region in Muslim Mindanao in 1993.
From 2011 to 2019, Tan was the Undersecretary of the Office of the President during the administrations of presidents Benigno Aquino III and Rodrigo Duterte. He was also the Undersecretary of the Office of Presidential Adviser on the Peace Process (OPAPP) and Implemented Panel Chair of the national government from May 2006 until 2019. He was appointed officer-in-charge of the OPAPP first in 2001, and again in October 2009, serving until November of the same year.
Tan was one of the 40 nominees of the national government to serve as members of the newly-established Bangsamoro Parliament in 2019. He was appointed to the Parliament by President Rodrigo Duterte, and was elected deputy speaker in the first interim Parliament. He was reappointed in 2022 and 2025 by President Bongbong Marcos.
After the death of incumbent speaker Pangalian Balindong in October 2025, Tan was considered as one of the candidates for the speakership, alongside fellow MP Jose Lorena. He instead supported and nominated Mohammad Yacob, who was unanimously elected by the Parliament to succeed Balindong on October 21, 2025.