The population growth and the limited reservoir of fossil resources have ignited the attention of scientific communities and entrepreneurs to produce alternative products with raw-materials from renewable sources. In this work, proteins derived from the recycling of waste textiles were studied as raw-material in the synthesis of thermosetting polymers of phenolic type (phenol-formaldehyde resins) suitable for use as adhesives in the production of wood-based panels. The physical, thermal, and morphological properties of the thermosetting polymers were investigated. For comparison reasons, a typical phenol-formaldehyde (PF) resin was also presented in this study. In detail, the chemical bonds between raw-materials and PF resins were verified with Fourier Transform Infrared spectroscopy (FTIR). The curing performance and thermal stability of the thermosetting PF resins were studied with Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA), respectively. Wood-based panels were prepared and tested at a lab scale following a simulation of the industrial practice. Optical Microscope and Scanning Electron Microscopy (SEM) were applied for the study of the interaction between PF resins and woodchips at the lab scale. It was found that the resins were successfully prepared. The maximum curing temperature of the experimental resins was shifted to higher values than the control PF. According to the TGA results, the protein-based resins seem to lose mass with a lower rate, which denotes that they are more thermally stable than a typical PF resin. It can be concluded that protein from waste textiles can effectively replace part of the petrochemical phenol in the PF resin synthesis, thereby increasing the bio-content of the PF resin and making them more friendly to the environment.