Fungi of the genus Trichoderma are a very large group of microorganisms that play a significant role in the environment. They use a variety of mechanisms to colonise various ecological niches. Several Trichoderma spp. positively affect plants by stimulating plant growth, and protecting plants from fungal and bacterial pathogens. They are used in biological plant protection as biofungicides as well as in bioremediation. Members of the genus Trichoderma are also utilised in various industry branches – mainly in the production of enzymes, antibiotics, and other metabolites, but also of biofuel. Moreover, the genus Trichoderma comprises edible and medicinal mushrooms, but also the pathogens of humans. Currently, Trichoderma has entered the genomic era and parts of genome sequences are publicly available. This is why, Trichoderma fungi have the potential to be used for human needs to an even greater extent than before. Nevertheless, further studies are needed to increase the efficiency and safety of the application of these fungi.