Understanding rice farmers’ responses to market prices is essential for policy makers to design effective policies to better manage input demand and rice supply. This paper applies duality theory to derive the elasticities of input demand and output supply for Vietnamese rice production using a translog profit function approach. We simultaneously estimate the translog profit function and its profit share equations using the seemingly unrelated regression method. This research uses primary farm-level data consisting of 918 observations surveyed in Vietnam’s Mekong River Delta.