The Pakistan government launched a nuclear power programme in the mid-1950s. At the time of launching the programme, there is no evidence that it intended to build nuclear weapons. In the 1960s, however, Pakistani attitude towards nuclear weapons modified slightly and the country adopted a nuclear option policy, which meant that it reserved the choice to build nuclear weapons in the future. The adoption of a nuclear option policy was manifested in Pakistan's decision not to sign the Non-Proliferation Treaty (NPT) in 1968. Following the nuclear tests, Islamabad announced that Pakistan would pursue a minimum deterrence posture and adopted a quantitative force-building approach to build the deterrent. This chapter examines the historical background of Pakistan's nuclear weapons programme, the rationale for building nuclear weapons, its post-tests nuclear force-building strategy, the challenges that Pakistan confronts in building and maintaining the deterrent and the possible directions of the Pakistani strategic weapons programme in the short to medium term.