Trioceros werneri, the Wemer's chameleon or Wemer's three-horned chameleon, is a species of chameleon that is endemic to forests and nearby gardens at altitudes of 1,700–2,600 m (5,600–8,500 ft) in the Eastern Arc Mountains of Tanzania.

[1][2] The adult male has three distinct "horns", whereas the female has no or only a single short horn on the nose.

[3][4] Like many (but not all) Trioceros species of highlands, the female T. werneri does not lay eggs, but instead gives birth to live young, typically 15–20 at a time.

[5] The three long annulated horns in the male T. werneri makes it superficially similar to T. jacksonii and T. johnstoni, and to extent also to the short-horned T. fuelleborni and the smooth-horned T. oweni,[3] but they are not close relatives.

[5] Although currently recognized as a single relatively widespread species, it is considered likely that T. werneri is a species complex and a taxonomic review is necessary.