Exposure to some toxic compounds causes structural and behavioral anomalies associated with the neurons in the later stage of life. Those toxic compounds are termed as a neurotoxicant, which can be a physical factor, a toxin, an infection, radiation, or maybe a drug. The incongruities caused due to a neurotoxicant further depend on the toxicity of the compound. More importantly, the neurotoxicity of the compound is associated with the concentration and the time point of exposure. The neurodevelopmental defect appears depending on the toxicity of the compound. A neurodevelopmental defect may be associated with a delay in developmental time, defective growth, structural abnormality of many organs, including sensory organs, behavioral abnormalities, or death in the fetus stage. Numerous model organisms are employed to assess the effect of neurotoxicants. The current review summarizes several methods used to check the effect of neurotoxicant and their effect using the model organism Drosophila melanogaster.