The official religion of Pakistan is Islam, as enshrined by Article 2 of the Constitution, and is practised by an overwhelming majority of 96.35% of the country's population. The remaining 3.65% practice Hinduism, Christianity, Ahmadiyya (considered a non-Muslim group as per the Pakistani constitution), Sikhism, Zoroastrianism and other religions.

Muslims comprise a number of sects: the majority practice Sunni Islam (estimated at 85-90%), while a minority practice Shia Islam (estimated at 10-15%). Most Pakistani Sunni Muslims belong to the Hanafi school of jurisprudence, which is represented by the Barelvi and Deobandi traditions. However, the Ahl-i Hadith movement has also gained popularity together with Wahhabi influence from the Middle East. The majority of Pakistani Shia Muslims belong to the Twelver Islamic law school, with significant minority groups who practice Ismailism, which is composed of Nizari (Aga Khanis), Mustaali, Dawoodi Bohra, Sulaymani, and others.

Before the arrival of Islam beginning in the 8th century, the region comprising Pakistan was home to a number of faiths, including Hinduism, Buddhism, Jainism and Zoroastrianism.

Khawaja Nazimuddin, Pakistan's second Prime Minister, argued against equal rights for all citizens in an Islamic state. The Constitution of Pakistan establishes Islam as the state religion, and provides that all citizens have the right to profess, practice and propagate their religion subject to law, public order, and morality. The Constitution also states that all laws are to conform with the injunctions of Islam as laid down in the Quran and Sunnah.

The Constitution limits the political rights of Pakistan's non-Muslims. Only Muslims are allowed to become the President or the Prime Minister. Only Muslims are allowed to serve as judges in the Federal Shariat Court, which has the power to strike down any law deemed un-Islamic, though its judgments can be overruled by the Supreme Court of Pakistan. However, non-Muslims have served as judges in the High Courts and Supreme Court. In 2019, Naveed Amir, a Christian member of the National Assembly moved a bill to amend the article 41 and 91 of the Constitution which would allow non-Muslims to become Prime Minister and President of Pakistan. However, Pakistan's parliament blocked the bill.

The main principles of Human rights in the Pakistani constitution were incorporated in its fundamental rights which were granted under various articles of 20, 21, 22, 25, 26, 27, 36 & 38 of the constitution –

(a) Article 20 : Freedom to profess religion and to manage religious institutions.

(b) Article 21 : Safeguard against taxation for purposes of any particular religion.