A system and method for estimating steam quality for a steam generator is provided which involves obtaining raw measurement values for process variables of the steam generator from sensors coupled to the steam generator; receiving the raw measurement values and slow-rate steam quality samples in order to determine a steam quality estimate, using a measurement module to receive the raw measurement values and determine model input values and a robustness index; using an estimator module to determines a raw steam quality estimate using the model input values and a model that is selected from several models depending on reliability of some of the raw measurements; and using a corrector module to determine the steam quality estimate using the raw steam quality estimate, robustness index, and slow-rate steam quality samples. An output receives the steam quality estimate and can provide the steam quality estimate to another device.