The aim of this thesis to high lights the Afghanistan complex situation and its implications on Pakistan. Though out the history, Afghanistan complex situation and weak government create a security threat for Pakistan. Since the late 1970s Afghanistan had suffered brutal civil war in addition to foreign interventions in the form of the 1979 Soviet invasion and the 2001 U.S. invasion. Pakistan is significantly and directly affected by the foreign invasion in Afghanistan. Pakistan is facing a variety of security threats; an internal threat, an Indian threat, and the threat from Afghanistan. In order to comprehend Pakistan's security dilemma, it is necessary to start our discussion with analyze the Afghanistan geographically importance, foreign intervention in Afghanistan, pak-afghan relation, Pakistan’s foreign policies towards Afghanistan, the resistance movement and refugee problems, and then evaluate the security situation. Admittedly, the India factor cannot be ignored in studying Pakistan's security dilemma.