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Forest–savanna boundaries extend across large parts of the tropics but the variability of photosynthetic capacity in relation to soil and foliar nutrients across these transition zones is poorly understood. For this reason, we compared photosynthetic capacity (maximum rate of carboxylation of Rubisco at 25 C° (V cmax25), leaf mass, nitrogen (N), phosphorus (P) and potassium (K) per unit leaf area (LMA, N area, P area and K area, respectively), in relation to respective soil nutrients from 89 species at seven sites along forest–savanna ecotones in Ghana and Brazil. Contrary to our expectations, edaphic conditions were not reflected in foliar nutrient concentrations but LMA was slightly higher in lower fertility soils. Overall, each vegetation type within the ecotones demonstrated idiosyncratic and generally weak relationships between V cmax25 and N area, P area and K area. Species varied significantly in their V cmax25 ↔ N area relationship due to reduced investment of total N area in photosynthetic machinery with increasing LMA. We suggest that studied species in the forest–savanna ecotones do not maximize V cmax25 per given total N area due to adaptation to intermittent water availability. Our findings have implications for global modeling of V cmax25 and forest–savanna ecotone productivity. [ABSTRACT FROM AUTHOR]