In late Qajar Iran, surveillance of the frontiers was driven by deep-seated anxieties over British, Ottoman and Russian encroachments on Iranian sovereignty and the yearning to finalize Iran’s territorial framework. Iran’s invasion during WWI gave rise to a particularly virulent strain of anti-colonial nationalism. In the aftermath of the war, the ongoing British presence in the south, particularly in the Persian Gulf, emerged as a focal point for protest and a constant reminder of Iran’s weakness and humiliating capitulations to Europeans. The rise of Reza Khan in 1921 (later Reza Shah Pahlavi, 1925-1941), was accompanied by the revival of territorial claims in the Persian Gulf, a sharp rejection of Britain's claim to protect Arab shaykhs on both sides of the Gulf, and a demand to revise the Iran-Iraq boundary. In the late Qajar period, Iran’s chief source of information about people and events on the Arabian Peninsula was its network of k?rgoz?rs (foreign ministry agents) that were stationed in Abadan, Bushehr, Lingah and Bandar Abbas. The office of the k?rgoz?r was abolished in 1928 along with the capitulations regime, and the responsibility for intelligence gathering shifted to Iranian diplomats in Baghdad, Karbala, Basra, Karachi, Cairo, and the Hijaz as well as European capitals. These officials, eager to participate in the struggle to liberate Iran from foreign domination, gathered knowledge about the British and their tribal protégés and sent detailed reports, country studies and policy recommendations to their superiors in Tehran. Their sources included transnational merchants in the Gulf, frontier populations and Arabic newspapers. Their representations of tribal rulers and tribal societies in Arabia were refracted through cultural animosities, experiences with colonial pressures and unresolved territorial questions. Using archival documents, this paper will examine politics on the Arabian Peninsula from an Iranian point of view, including the Saudi-Rashidi war (1903-1907); the 1922 palace coup in Abu Dhabi; the Ikhwan revolt and the unification of Saudi Arabia (1927-1932); Iraqi Prime Minister Nuri al-Said’s scheme for Gulf Arab unification (1930-1932); and the 1938 majlis movements in Kuwait and Dubai. Official country surveys and intelligence reports, and the responses they elicited from Tehran, afford a unique window into the history and practice of surveillance in late Qajar and early Pahlavi Iran as well as Iranian perceptions of state formation on the Arabian Peninsula, tribal politics in the Gulf shaykhdoms and Oman, and Britain’s role in the region.