For a good development of species with great economic value such as: Khaya senegalensis, which is exotic in Brazil, it is necessary analyzes of intrinsic characteristics to obtain responses of good adaptation to edaphoclimatic conditions in various regions of the country. Thus, the objective of this work was to investigate morphophysiological responses of seedlings of Khaya senegalensis under luminosity levels. An experiment was set up in the forest nursery at ''Universidade Federal do Tocantins'' , distributed in a completely randomized design, divided into five treatments in luminosity levels (full sun, 70, 50, 30% and Natural Shade). Over the months, physiological measurements were taken (Assimilation of CO 2 , Transpiration and stomatal conductance) and morphological (Height and DBH) with intervals of 30 days. At the end of the experiment, the total biomass and mass fractions (leaf, stem, root and total) were obtained. With that, there were significant results among the treatments tested for the species: Khaya senegalensis, because the levels of luminosity influenced the development of the seedlings, which obtained the highest growth rates in plants under partial levels (70, 50 and 30%) of luminosity. And also the physiological responses such as photosynthesis, transpiration and stomatal conductance were higher in high luminosity levels. That said, for the best initial development of the species: Khaya senegalensis regarding luminosity, it was evident that the partial levels (70, 50, 30%) favored the growth and quality of the seedlings, but the low level of light that arrives in the natural shade was not enough to guarantee the vigor of the African mahogany seedlings.