Food security is threatened by biotic stress on crops, e.g., from invasive pests, in the context of climate change. Pest control has traditionally been achieved using synthetic pesticides, yet pollution and the persistence and toxicity of some pesticides are inducing food contamination and, in turn, generating public concern. As a consequence, biopesticides are increasingly used, notably for organic crops. For instance, some microorganisms produce biopesticidal compounds such as secondary metabolites or growth-inhibitory enzymes. Most reviews on this topic mainly focus on describing microbial species and their active compounds. However, there are very few studies and reviews describing various process parameters. Here, we review both microbial biopesticides and factors controlling physicochemical conditions for the scaling up of biopesticide production. We present biopesticides from bacteria (e.g., Bacillus thuringiensis), algae, fungi, and viruses and review the biocontrol mechanisms and applications of commercial biopesticides. The benefits of genetic engineering for enhancing activity and drawbacks such as commercialization are also discussed.