The Intelligence Bureau (Urdu: انٹیلی جنس بیورو ; IB) is an intelligence and security agency in Pakistan, focused primarily on non-military intelligence. Established in 1947, the IB is Pakistan's oldest intelligence agency. It is led by the Director General (DG IB), who is usually an officer from the Police Service of Pakistan.

The government of Pakistan elevated the Intelligence Bureau status from a semi-autonomous agency to a Division, upgrading it to the equivalent of a Federal Ministry, under oversight of a federal secretary. Appointments and supervision of its operations are authorized by the Prime Minister of Pakistan.

The Intelligence Bureau traces its origin to the Central Special Branch, established on 23 December 1887 by the British government in India to gather intelligence on political unrest. Its creation followed Secret Dispatch No. 11, dated 25 March 1887, in which R. A. Cross, the Secretary of State for India, sanctioned the proposal by Lord Dufferin, the Viceroy of India, to create a system for the "collection of secret and political intelligence in India".

Dufferin proposed utilizing the police forces in British India and political officers in princely states for the "collection of intelligence on political, social and religious movements". He recommended the establishment of "special agencies" at both central and provincial headquarters. The Provincial Special Branches, under local government control, were tasked with sharing intelligence with the Central Special Branch. Dufferin modelled the agency after the Third Section of Imperial Russia. To reduce expenses, the agency shared the manpower and facilities of the existing Thuggee and Dacoity Department. The General Superintendent of the Department was entrusted with the supervision of the Central Special Branch. The Provincial Special Branches were attached to the offices of either the Inspector General of Police or the chief secretary of the respective provinces.

In 1904, based on the recommendations of the Indian Police Commission (1902 – 1903) chaired by Andrew Fraser, the Central Criminal Intelligence Department—also known as the Department of Criminal Intelligence (DCI)—was established. This reorganization led to the abolition of the Thuggee and Dacoity Department and the merger of the Central Special Branch into the DCI. Additionally, Criminal Investigation Departments (CID) were created in the provinces. Initially, Provincial Special Branches were incorporated into the CIDs, but they were later separated as their functions evolved.

Section 40(2) of the Government of India Act 1919 stated that "the Intelligence Bureau should keep the Government posted with matters relating to the security of the Indian Empire." Reflecting this directive, the DCI was renamed the Intelligence Bureau in 1920, a year before the Act formally came into force in 1921.

In the aftermath of the independence of Pakistan by the British Crown, the IB, like the armed forces was partitioned, with a Pakistan IB created in Karachi. Since, the IB is the oldest intelligence community; others being the Military Intelligence (MI) of Pakistan's military. The IB was initially Pakistan's only and main intelligence agency with the responsibility for strategic and foreign intelligences, as well as counter-espionage and domestic affairs.

Its poor performance with the MI and unsatisfactory detailing of the war with India in 1947 was however considered less than exemplary. Due to the fact, IB was concerned with internal security matters, and was not set up for foreign intelligence collection. These considerations ultimately led to the creation of the ISI in 1948 as it quickly took the charge of gathering strategic and foreign intelligence at all levels of command.