Mount Kenya, with its rich plant diversity, is among the famous tropical mountains in the world, and is the second highest mountain in Africa after Mount Kilimanjaro. An annotated checklist of the vascular plants of Mount Kenya was compiled through several approaches including our own collections from 2009 to 2018. A total of 1 545 vascular plants are found on Mount Kenya, including 1 481 indigenous and 64 exotics. The indigenous species are represented by nine lycophytes (five genera, two families), 129 ferns (56 genera, 20 families), three gymnosperms (three genera, two families), and 1 340 angiosperms (624 genera, 132 families). Trees constitute 9.92% of the flora, shrubs 15.99%, lianas 3.10%, climbers 4.45%, herbs 57.22%, lycophytes 0.61%, and ferns 8.70%. The two types of forest vegetation (lower montane wet forest and lower montane dry forest) have the highest and nival zone have the lowest species richness. In total, 18.96% of the species are distributed in Africa and other continents, 60.26% are endemic to Africa, 12.17% are endemic to Tropical East Africa, 3.17% are endemic to Kenya, 1.29% are endemic to Mount Kenya, and 4.14% are exotic plants. These results provide foundational data for further studies, and also provided support for the local government to formulate conservation policies.