The post contains answer to questions “Who imposed third martial law in Pakistan? Who enforced third martial law in Pakistan?”
Who imposed third martial law in Pakistan?
Third martial law in Pakistan was imposed by General Muhammad Zia ul Haq
In Pakistan third martial law was imposed by the then commander in chief of Pakistan army, General Muhammad Zia ul Haq. On 5th July 1977, General Zia ul Haq ousted the then Prime Minister of Pakistan, Zulfiqar Ali Bhutto and became the Chief Martial Law administrator.
Zia ul Haq remained Chief Martial Law administrator from 5th July 1977 to 16th September 1978, when he became the Sixth president of Pakistan.
Source: The source of above answer is History Books of Pakistan