Senega lewtonii is a rare species of flowering plant in the milkwort family known by the common name Lewton's polygala, or Lewton's milkwort. It is endemic to Florida in the United States, where it is limited to the central ridge of the peninsula. There are about 49 occurrences of the plant remaining. Most occurrences contain very few plants. The species is threatened by the loss and degradation of its habitat. This is a federally listed endangered species of the United States.