An experiment was carried out in a naturally ventilated greenhouse to study the relationship between banana (Musa sp.) plant transpiration (Tr) measured with load cells, reference crop evapotranspiration (ETo) calculated with five widely used models (i.e. the Priestley-Taylor, FAO radiation, Hargreaves, FAO Penman and FAO Penman-Monteith models) and pan evaporation (Epan) measured with a standard Chinese 20 cm pan. Microclimatic conditions were measured inside the greenhouse. Results show that vapor pressure deficit and air temperature had good linear correlations to banana Tr with R2 of 0.67 and 0.62, respectively. Among the five models tested, banana Tr and ETo calculated with the FAO-Penman model yielded the highest determination coefficient (R2 = 0.67), followed by the FAO-PM model (R2=0.63), the FAO radiation model (R2=0.52), the Hargreaves model (R2=0.49) and the Priestley-Taylor model (R2=0.47). Banana transpiration Tr vs. Epan yielded an R2 of 0.83, which is higher than the five models tested. In conclusion, the 20 cm pan can be useful for estimating banana Tr in greenhouses.