Methods, apparatus, systems and articles of manufacture are disclosed for machine learning engine optimization. An example apparatus includes a selection metric analyzer to compute a first selection metric based on a first set of ordered output values from a first candidate machine learning engine and a set of reference data values; compute a second selection metric based on a second set of ordered output values from a second candidate machine learning engine and the set of reference data values; and a machine learning engine replacer to determine whether to replace an active machine learning engine with at least one of the first candidate machine learning engine or the second candidate machine learning engine based on the first selection metric and the second selection metric.