Snakes of the genus Leptophis are slender with a long tail. The body is cylindrical or slightly laterally compressed. The head is elongated and distinct from the neck. The eye is large with a round pupil. The dorsal scales are arranged in 15 rows at midbody.
The maxillary teeth, which number 20-32, are in a continuous series without any interspace, and are longest posteriorly, but without grooves. Conversely, the mandibular teeth are longest anteriorly.