Systems, methods, and articles of manufacture to control a multiple-fuel steam production system are disclosed. An example method obtains a plurality of input values associated with producing steam and uses a model predictive controller to determine a first value associated with predicting an amount of a first fuel and a second value associated with predicting an amount of a second fuel to produce an amount of steam. Fuel feed rates of the first and second fuels are then controlled based on the first and second trajectory values.