The study attempts to evaluate the phenomenon of Talibanization in Pakistan. Taliban emerged in Afghanistan and after 9/11 became active in Pakistan. The active participation of Pakistan in the War against Terrorism and military actions against terrorist groups operating from the tribal region gave rise to militancy and Talibanization. The country has been dealing with militancy and insurgency since 2002. The study focuses on the role of Taliban and other extremist/militant groups who share Taliban’s ideology and are active in Pakistan. Besides Taliban’s ideology and actions have impacted Pakistani society and politics in many ways, Pak-US relations, internal security, especially in FATA, and economic and social development. The research is based on the conceptual model of insurgency assessment. The study traces the history of Talibanization and underscores the different sub-organizations that are working under the umbrella of Taliban. The study suggests that military operations should be consistent against TTP/Al-Qaeda and all other terrorist factions. Combined operations involving security forces and law enforcement agencies should be carried out based on accurate intelligence consistent with national goals. While Pakistan’s government has taken serious steps, like National Action Plan, to address extremism / terrorism, Talibanization continues to have an impact on Pakistan’s internal security.