The House and Merit Order of Duke Peter Frederick Louis or proper German Oldenburg House and Merit Order of Duke Peter Frederick Louis was a civil and military order of the Grand Duchy of Oldenburg, a member state of the German Empire. The order was founded by Grand Duke Augustus of Oldenburg on 27 November 1838, to honor his father, Peter Frederick Louis of Oldenburg. It became obsolete in 1918 after the abdication of the last grand duke.

Augustus I or Paul Frederick Augustus was the reigning Grand Duke of Oldenburg from 1829 to 1853.