Tannerella forsythia is a gram negative bacteria inhabiting human gingival tissue. It is a member of a bacterial consortium known as the red complex. This consortium is connected to the development of periodontal disease and several other conditions. T. forsythia contributes to periodontal disease development by inducing dysbiosis in oral microbial community and suppressing the host immune response. It achieves this via a number of virulence factors. Major T. forsythia virulence factors can be divided into proteases, glycosidases and cell membrane and cell wall associated proteins. Most T. forsythia proteases partake in virulence via degradation of host tissue and suppression of immune signalling via interleukins. T. forsythia glycosidases are taught to degrade extracellular polysaccharides and proteoglycans, thereby reshaping the gingival environment and providing nutrients. The outer membrane protein BspA is likely involved in adhesion of bacterial cells to tissue surface and interactions with other periodontal bacteria. T. forsythia serpin, known as miropin, is taught to partake in inhibition of neutrophil serine proteases. The S-layer of T. forsithya, uniquely composed of two glycosylated components TfsA and TfsB, regulates biofilm formation, tissue invasion and immunosuppression. Outer membrane vesicles deliver these virulence factors to host cells. These virulence factors provide possible targets for future therapies of periodontal diseases.