Álvaro de Navia-Osorio y Vigil, 3rd Marquis of Santa Cruz de Marcenado and Viscount of Puerto, born in 1684 in Santa Maria de Vega in Asturia, Spain; killed in action near Oran in North Africa in 1732, was a Spanish diplomat, general, and author. At the time of his death in battle fighting off an attack by Ottoman forces in 1732 he was governor of the Spanish possession of Oran in North Africa.
Between 1726 and 1730, Santa Cruz de Marcenado wrote seven volumes of Military Reflections, published in Turin and Paris. One volume deals specifically with the prevention of insurgencies and counter-insurgency campaigns. Santa Cruz was probably the earliest author who gave systematic attention to this subject.