A liquid crystal alignment agent capable of forming a liquid crystal alignment film having good ultraviolet reliability, the liquid crystal alignment film, and a liquid crystal display element having the same are provided. The liquid crystal alignment agent includes a polymer (A) and a solvent (B). The polymer (A) is obtained by reacting a mixture. The mixture includes a tetracarboxylic dianhydride component (a) and a component (b). The component (b) includes a diamine compound (b-1) represented by formula (1), a diamine compound (b-2) represented by formula (2), and a compound (b-3), wherein the compound (b-3) is at least one selected from the group consisting of a structure represented by formula (3-1) and a structure represented by formula (3-2).