Anacithara undaticosta is a species of sea snail, a marine gastropod mollusc in the family Horaiclavidae. In 1994 R.N. Kilburn disputed the attribution by Charles Hedley (1922) of Pleurotoma undaticostata Reeve, 1845 to the genus Anacithara, because the original figure by Reeve showed a shell that is too fusiform, and lacked further detail. The holotype of this species as described by Reeve is lost, making it impossible to describe this species accurately.