This study presents a method to separate mechanical strain from charge doping in graphene using Raman spectroscopy. The Raman G and 2D modes are sensitive to both strain and charge doping, but by analyzing their correlation, the effects can be distinguished. The results show that graphene on silica substrates experiences in-plane strain ranging from -0.2% to 0.4%, which is reduced and becomes compressive upon thermal treatment. Thermal annealing at 100°C or higher leads to significant changes in the Raman modes, indicating strain relief and hole doping. The study demonstrates that strain and charge doping can be quantified independently, with strain being the dominant factor in the spectral variations. The analysis is validated using a vector decomposition approach, which allows for the separation of strain and charge contributions. The results suggest that mechanical strain is a common phenomenon in two-dimensional materials, and the proposed method can be used for the characterization of graphene-based materials and devices. The study also highlights the importance of considering both strain and charge effects in the interpretation of Raman spectra of graphene.This study presents a method to separate mechanical strain from charge doping in graphene using Raman spectroscopy. The Raman G and 2D modes are sensitive to both strain and charge doping, but by analyzing their correlation, the effects can be distinguished. The results show that graphene on silica substrates experiences in-plane strain ranging from -0.2% to 0.4%, which is reduced and becomes compressive upon thermal treatment. Thermal annealing at 100°C or higher leads to significant changes in the Raman modes, indicating strain relief and hole doping. The study demonstrates that strain and charge doping can be quantified independently, with strain being the dominant factor in the spectral variations. The analysis is validated using a vector decomposition approach, which allows for the separation of strain and charge contributions. The results suggest that mechanical strain is a common phenomenon in two-dimensional materials, and the proposed method can be used for the characterization of graphene-based materials and devices. The study also highlights the importance of considering both strain and charge effects in the interpretation of Raman spectra of graphene.