AbstractMountain forest soils contain an important stock of carbon. Their altitudinal gradient can serve as a model for research on the potential risk of increased emission of carbon dioxide to the atmosphere, in a positive feedback of global warming. Using soil samples collected at three elevations (600, 900, and 1200 m a.s.l.) from five separate slopes of the Carpathian Mountains (Poland), we studied the effects of soil physical, chemical and microbial properties controlling the temperature sensitivity (Q10 values) of organic matter decomposition in forest soils. Data of soil basal respiration rate measured in laboratory conditions at six different temperatures (5, 10, 15, 20, 25 and 30 °C) were fitted to a Gaussian function. The modelled soil respiration rates differed between altitudes at temperature exceeding 15 °C, and the respiration rate of soil from 1200 m a.s.l. was higher than in soils from the two lower elevations. Based on the modelled respiration values, we calculated Q10 values in the low (Q10L, 0–10 °C), medium (Q10M, 10–20 °C) and high (Q10H, 20–30 °C) temperature ranges. The Q10 values did not differ between elevations. Q10L and Q10M were negatively related only with the C:N ratio. Temperature sensitivity of decomposition of soil organic matter was not affected by bacterial activity and functional diversity (assessed using Biolog® ECO plates), microbial biomass or community structure (inferred from phospholipid fatty acid assays). Our findings support a kinetics‐based theory of the higher temperature sensitivity of more chemically recalcitrant soil organic matter, put forward by other authors.