Operation Gordian Knot was the largest and most expensive Portuguese military campaign in the Portuguese overseas province of Mozambique, East Africa. The operation was carried out in 1970, during the Portuguese Colonial War (1961–1974). The objectives of the campaign were to close down the Mozambique Liberation Front (FRELIMO)'s infiltration routes across the Tanzanian border and to destroy permanent FRELIMO bases inside the liberated zones in Northern Mozambique. Gordian Knot was a seven-month long campaign ultimately employing thirty-five thousand men, and was almost successful since it destroyed most guerrilla camps located inside FRELIMO's liberated zones and captured large numbers of rebels and armaments, forcing FRELIMO to retreat from their bases and outposts in the provinces. The operation ultimately failed when FRELIMO forces regrouped and thrust further south into the province of Tete, opening a new front and overstretching the Portuguese Army. The failure of Gordian Knot helped fuel the discontent that led to the Carnation Revolution in April 1974.

FRELIMO is a democratic socialist political party in Mozambique. It has been the country's ruling party since 1977.