Bacillus thuringiensis (Bt) is a Gram-positive, soil-dwelling bacterium that is commonly used in biological pest control. It produces crystal proteins that are toxic to certain insects, particularly Lepidoptera larvae (moths and butterflies), mosquitoes, and beetles. These proteins are commonly incorporated into insecticidal sprays and genetically modified crops to protect them from insect damage. Research on Bacillus thuringiensis explores its potential as a sustainable alternative to chemical pesticides, its effectiveness in controlling insect pests while minimizing harm to non-target organisms, and its potential applications in agriculture, forestry, and public health. Studies also focus on understanding the mechanisms of action of Bt toxins, developing new strains with enhanced insecticidal activity, and studying the evolution of resistance in target insect populations.