Standing's day gecko Phelsuma standingi is one of the largest and yet most poorly studied geckos in Madagascar. We report the discovery of a substantial northern range extension and document a previously unrecognized association between this gecko and baobab trees in southwest Madagascar. At three survey sites we found P. standingi associated with three baobabs: Adansonia grandidieri in northwest Morombe, A. rubrostipa at Ranobe and A. za at Zombitse Reserve. Although P. standingi is not an obligate baobab tree specialist, these massive trees appear to offer secure refuge and climbing surfaces, and baobabs are the main microhabitats occupied by these large day geckos. This unrecognized gecko-baobab association might partly explain why so few field observations have been made previously for P. standingi.