In recent years, biochar has attracted considerable attention due to its unique characteristics and wide applications in agricultural and environmental areas. Biochar is recognized for its potential role in carbon sequestration, reduction of greenhouse gas emissions, soil amendment, bioenergy production and waste mitigation. The current review discusses on the utilization of various lignocellulosic and lignin-based feedstocks for the biochar production. However, the quality of biochar varies among different thermo-conversion technologies due to the differences in their key process parameters and the feedstock composition. This article aims to review two production technologies for lignocellulosic and lignin-based biochar, namely, slow pyrolysis and fast pyrolysis. The effects of feedstock composition (cellulose, hemicellulose, lignin) and pyrolysis conditions such as temperature and heating rate on the quality of biochar are compared. The relationship between the feedstocks composition, temperature, heating rate of pyrolysis and the quality of biochar are also discussed. Future work would further correlate the effects of feedstock composition and process parameters on the quality of biochar such as surface area and functionality.