The origin of the name Kilimanjaro is not known, but a number of theories exist. European explorers had adopted the name by 1860 and reported that Kilimanjaro was the mountain's Swahili name. The 1907 edition of The Nuttall Encyclopedia also records the name of the mountain as Kilima-Njaro.
Johann Ludwig Krapf wrote in 1860 that Swahilis along the coast called the mountain Kilimanjaro. Although he did not offer any support. he claimed that Kilimanjaro meant either mountain of greatness or mountain of caravans. Under the latter meaning, kilima meant mountain and jaro meant caravans. Jim Thompson claimed in 1885, again without support. that the term Kilima-Njaro "has generally been understood to mean" the mountain (kilima) of greatness (njaro). He also suggested "though not improbably it may mean" the white mountain.
Njaro is an ancient Kiswahili word for shining. Similarly, Krapf wrote that a chief of the wakamba people whom he visited in 1849, "had been to Jagga and had seen the Kima jajeu, mountain of whiteness, the name given by the Wakamba to Kilimanjaro. More correctly in the Kikamba language this would be kiima kyeu, and this possible derivation has been popular with several investigators.

Others have assumed that kilima is Kiswahili for mountain. The problem with this assumption is that kilima actually means hill and is, therefore, the diminutive of mlima, the proper Kiswahili word for mountain. However, that an early European visitor, whose knowledge of [Kiswahili] was not extensive, changed mlima to kilima by analogy with the two Wachagga names: Kibo and Kimawenzi. A different approach is to assume that the kileman part of Kilimanjaro comes from the Kichagga kileme, which means that which defeats, or kilelema, which means that which has become difficult or impossible. The jaro part would "then be derived from njaare, a bird; or, according to other informants, a leopard; or, possibly from jyaro, a caravan". Considering that the name Kilimanjaro has never been current among the Wachagga people, it is possible that the name was derived from Wachagga saying that the mountain was unclimbable, kilemanjaare or kilemajyaro, and porters misinterpreting this as being the name of the mountain.
In the 1880s, the mountain became a part of German East Africa and was called Kilima-Ndscharo in German following the Kiswahili name components. On 6 October 1889, Hans Meyer reached the highest summit on the crater ridge of Kibo. He named it Kaiser-Wilhelm-Spitze (Kaiser Wilhelm peak). That name was used until Tanzania was formed in 1964. when the summit was renamed Uhuru Peak, meaning freedom peak in Kiswahili.