Wood ash, the by-product of biomass combustion to energy, can return important nutrients back to the soil and counteract acidification. However, the application of wood ash may affect the emission of greenhouse gases. Here, the effect of wood ash application on nitrous oxide (N₂O) emissions from different soil environments were investigated in a 40 days incubation experiment comprising ten different soil types amended with five different wood ash concentrations (0, 3, 9, 20, and 54 t ash ha⁻¹). The emitted N₂O was measured continuously, and initial soil properties without ash application (carbon (C), nitrogen (N), ammonium (NH₄ ⁺), nitrate (NO₃ ⁻), and pH) and resulting soil properties (pH, NH₄ ⁺, and NO₃ ⁻) were measured prior and after the incubation period, respectively. The Random Forests (RF) model was used to identify which factors (initial and resulting soil properties, vegetation, management, wood ash doze, and respiration rate) were the most important to predict the development of emitted N₂O after ash application. Wood ash either increased, decreased, or had no effect on the amount of emitted N₂O depending on soil type and ash dose. The RF model identified the final resulting pH as the most important factor for the prediction of emitted N₂O. The results suggest that wood ash can mitigate N₂O emissions from soil, however, this effect depends on soil type where a mitigating effect of wood ash application was observed mainly in low pH soils with high soil organic matter whereas an increase in N₂O emissions was observed in mineral soils that had previously received N fertilization. This study emphasises the importance of pH manipulation in regards to N₂O emissions from soil.