Abstract: The present invention provides an actinic ray-sensitive or radiation-sensitive resin composition having excellent defect suppressing properties, a resist film, a pattern forming method, and a method for manufacturing an electronic device. The actinic ray-sensitive or radiation-sensitive resin composition according to an embodiment of the present invention is an actinic ray-sensitive or radiation-sensitive resin composition including a resin A having a repeating unit a1 having a group represented by any one of General Formula (1), . . . , or (6), which is a nonionic group that decomposes upon irradiation with actinic rays or radiation, and an additive B that is at least any one of an acid having an acid group having a pKa of ?3.60 or more, or a salt having a structure in which a hydrogen atom of an acid group having a pKa of ?3.60 or more is substituted with a cation.