Background: An ethnobotanical study was conducted in the eight regions of Niger to identify local knowledge variation of millet (Pennisetum glaucum (L.) R. Br) uses. In fact, the level of individual knowledge can be affected by many factors such as gender, age, ethnicity, occupation, religious and cultural beliefs, etc. This study documented indigenous knowledge of millet uses in Niger and aimed specifically to (i) identify the different types of millet organ uses and (ii) assess the variation of local knowledge of millet uses along with ethnicity, occupation, and age., Methods: The data were collected in 32 major millet-producing villages in Niger through individual semi-structured interviews and focus group discussions. About 508 individuals from 5 ethnic groups were interviewed. The assessment of the knowledge was performed by calculating five ethnobotanical indices such as the number of reported uses by parts of the plant (RU), the use-value of the parts of the plant (PPV), the specific use-value (SU), the intraspecific use-value (IUV), and the relative frequency of citations (FRC). Data were analyzed using descriptive, univariate, and multivariate statistical analyses., Results: The results indicated a significant variation in uses across ethnic groups (H = 38.14, P = 0.000) and socio-occupational categories (H = 6.80, P = 0.033). The Hausa, Kanuri, and Zarma-Sonhrai ethnic groups, farmers were the largest users of the species. Dietary (51.40%) and forage (40.35%) were the most reported uses. The most commonly used parts of the plant were the stubble (74.92%) and grains (73.68%)., Conclusions: The study showed the importance of P. glaucum in the daily life of local people. It also confirmed the uneven distribution of indigenous knowledge of millet uses in Niger due to social factors. Now, the challenge is how to incorporate these social differences in knowledge of millet uses in view to sustainable management and conservation of local genetic resources of millet. Finally, this work could be an important decision-making tool for future millet valuing.