The Messenger of Allah ﷺ called the gecko a "little noxious creature," but I did not hear him order that it be killed.
حدثنا بشر بن شعيب بن أبي حمزة قال وأخبرني أبي قال محمد أخبرني عروة أن
أن رسول الله ﷺ قال للوزغ فويسق ولم أسمعه أمر بقتله
Its isnad is sahih, but it has been narrated from her that the Prophet ﷺ commanded that geckos be killed and encouraged doing so, and the matter has already been explained for the sake of remembering the command. The hadith was narrated by Bukhari 6/351 no. 3206 in the chapter on the beginning of creation, Muslim 4/1758 no. 2239 in the chapter on greetings, Nasai 5/189 no. 2831 in the chapter on the rites of pilgrimage, and Ibn Majah 2/1076 no. 3206 in the chapter on hunting.