The presented studies concern the effects of graphite flake (GF) on the properties of a specific and challenging type of composite, that is, phenolic-carbon fabric (PC) composites. This type of materials are commonly used in large scale, but the studies in this manuscript try to explain in detail the effects of graphite on the characteristics of composites. The results show that Young's modulus exhibits increasing trend however tensile strength and interlaminar shear strength show decrement on increasing the GF content in the PC-GF composites. Dynamic mechanical thermal analysis (DMTA) reveals that storage modulus (E ') increases by similar to 42% and 139% upon addition of 10 and 40 wt% GF in the PC-GF composites, respectively. Loss modulus (E '') of the composites shows a drastic improvement (similar to 145%) upon addition of only 10 wt% GF. Moreover, various interfacial interaction parameters such as entanglement density (N), reinforcement efficiency factor (r), C factor (the effectiveness of fillers on the modulus of the composites), interphase adhesion factor (A), and 'b' factor (fiber volume correction factor) of the composites are also evaluated using the data obtained from DMTA and correlated with mechanical properties of the composites. POLYM. ENG. SCI., 58:1987-1998, 2018. (c) 2017 Society of Plastics Engineers