In recent years, due to increasing concerns about the environment and sustainable production, the effective utilization of wastes has become important. In this regard, it has become essential to obtain products with distinct properties by utilizing different types of biomass together. The world’s annual apricot production is approximately 4 million tonnes. The apricot seeds can be used to produce seed oils; however, remaining residue (apricot seed pulp) from this process is considered as waste. In this study, the co-pyrolysis of waste from the essential oil industry (apricot seed pulp, ASP, and by-products of the paper pulp industry (calcium lignosulfonate, CLS, and sodium lignosulfonate, SLS)) was carried out using mixtures at different temperatures (400–700 °C) and different ratios (4:1, 1:1, 1:4). The effects of temperature and ratio on the yields, composition, and HHV of biochars were investigated. Among biochars obtained from co-pyrolysis, the maximum HHVs of 26.91 MJ·kg⁻¹ and 25.64 MJ·kg⁻¹ were obtained for 5ASP-5CLS-400 biochar and 8ASP-2SLS-400 biochar, respectively. The results showed that the addition of ASP to CLS led to an increase in the HHVs of biochars when compared to the HHVs of biochars obtained from the pyrolysis of CLS. The use of two different types of waste has led to the production of biochars with different properties due to the synergistic effect in the pyrolysis. As a result, biochars with diverse properties, which have the potential to be utilized in various applications, were produced from different types of wastes.