The present disclosure provides engineered proline hydroxylase polypeptides for the production of hydroxylated compounds, polynucleotides encoding the engineered proline hydroxylases, host cells capable of expressing the engineered proline hydroxylases, and methods of using the engineered proline hydroxylases to prepare compounds useful in the production of active pharmaceutical agents. The present disclosure provides engineered proline hydroxylase biocatalysts, polynucleotides encoding the biocatalysts, methods of their preparation, and processes for preparing hydroxylated compounds using these engineered biocatalysts.