Increasing demand for animal protein has a negative consequences human health and the environment. Thus, the need for a replacement of animal protein with plant-based protein in human diet. The demand for selected plant-based protein (PBPs) (soybean, mushroom, potato, and cowpea) was therefore assessed. Data collected from 343 staffers of university of Ibadan were analysed using descriptive statistics and Quadratic Almost Ideal Demand System. Mushroom and soybean were luxury goods but demand for mushroom was more elastic than soybean. Potato was considered a necessary good.  Expenditure elasticity for cowpea was however found to be just unitary. The selected plant-based proteins were normal goods. Furthermore, all the compensated own-price elasticities (except mushroom) were less than one (in absolute terms) indicating that they are price-inelastic. They ranged between (-0.14) for soybean and (-0.62) for potato. Hicksian elasticities showed that mushroom was a substitute for cowpea and potato. Cowpea and potato were also substitutes to each other. Socio-economic factors influencing demand were years of schooling, access to market, prices of the PBPs and marital status of the respondent.