Provided is a detergent-dispersant for a lubricant having excellent detergency and dispersibility effects. Specifically provided are: a detergent-dispersant including a heterocyclic compound having a heterocyclic skeleton derived from a compound selected from the group consisting of pyridines, pyrroles, pyrimidines, pyrazoles, pyridazines, imidazoles, pyrazines, triazines, triazoles, tetrazoles, oxazoles, oxadiazoles, thiazoles, thiadiazoles, furans, dioxanes, pyrans, and thiophenes; and an additive composition for a lubricant and a lubricant composition, each containing the detergent-dispersant.