We show here the first colloidal synthesis of double perovskite Cs₂AgInCl₆ nanocrystals (NCs) with a control over their size distribution. In our approach, metal carboxylate precursors and ligands (oleylamine and oleic acid) are dissolved in diphenyl ether and reacted at 105 C with benzoyl chloride. The resulting Cs₂AgInCl₆ NCs exhibit the expected double perovskite crystal structure, are stable under air, and show a broad spectrum white photoluminescence (PL) with quantum yield of∼ 1.6±1%. The optical properties of these NCs were improved by synthesizing Mn-doped Cs₂AgInCl₆ NCs through the simple addition of Mn-acetate to the reaction mixture. The NC products were characterized by the same double perovskite crystal structure, and Mn doping levels up to 1.5%, as confirmed by elemental analyses. The effective incorporation of Mn ions inside Cs₂AgInCl₆ NCs was also proved by means of electron spin resonance spectroscopy. A bright orange emission characterized our Mn-doped Cs₂AgInCl₆ NCs with a PL quantum yield as high as∼ 16±4%.