Ecosystem services are fundamental to people and are undergoing many threats such as uncontrolled fire. Local knowledge has been widely used to guide management decisions for plant biodiversity. Therefore, we assessed the knowledge of the people of Pendjari Biosphere Reserve (PBR) on the impact of fire on ecosystem services (ES). A semi‐structured questionnaire with three fire impact levels (no, low and high) was used to interview 150 randomly selected households in four ethnic groups. The generalised linear model (GLM) was performed on the relative frequency of quotations to assess the effect of ethnic group, age and sex for each impact level of fire on ES and also to test the interaction among the considered factors. The local people reported that uncontrolled fire causes damage to many provisioning ES. The local knowledge concerning the impact of fire on ES was affected significantly (p < 0.0001) by ethnic group, age and sex irrespective of the impact level of fire on ES. Moreover, there was no significant interaction among the considered factors. The studied factors are benchmarks to be integrated into awareness and preservation measures of ES to mitigate the impact of uncontrolled fire practices in the study area.