Lusoga (JE16) is a largely undocumented Great Lakes Bantu language and only primers and basic grammatical descriptions were available at the beginning of this study. At the time, the existing literature did not even clearly state what ‘Lusoga’ constitutes. The main aim of this study was to document Lusoga. Accomplishment of this aim required the study to address four specific problems and this was done as follows. Firstly, this study gives an account of the historical factors that have shaped the status of Lusoga in Busoga and Uganda since the inception of the Busoga kingdom and the Republic of Uganda. Secondly, the historical background and the current status of the language varieties spoken in the region which are commonly regarded as ‘Lusoga’ are given. Thirdly, by specifying what Lusoga is and what it constitutes, this study also established that the main variety of Lusoga is Lutenga and that, conversely, it is this variety which is generally known as Lusoga. Fourthly, this study gives the first comprehensive description of the Lusoga grammar. This grammar is mostly descriptive in nature. It is heavily based on observations from natural language occurring in a corpus consisting of 1.7 million running words. Other methods of research used in addition include independent findings from focused fieldwork studies and the use of my mother-tongue intuition whenever necessary. The structure of the grammar is additive, in that the study connects and coheres from sound to word to phrase to clause. For the word level in particular, all the main parts of speech are looked at, one at the time. The study is concluded with a brief discussion and prospects for future research.