Frederick Augustus of Württemberg-Neuenstadt (Neuenstadt am Kocher, 12 March 1654 – 6 August 1716 in Gochsheim) was Duke of Württemberg and second Duke of Württemberg-Neuenstadt.
Frederick Augustus was the first-born child of Duke Frederick of Neuenstadt who established the second branch line of the Duchy of Württemberg-Neuenstadt. His wife was Clara Augusta of Brunswick. The branch line of Württemberg-Neuenstadt held responsibility for the town of Neuenstadt am Kocher, Möckmühl and parts of Weinsberg. They bore the title of duke although they held no state sovereignty which remained within the main duchy of Württemberg.
In 1674 the state became embroiled in the Franco-Dutch War. Frederick Augustus sided with Brunswick-Lüneburg, joining their regiment as a Rittmeister (a commissioned cavalry officer in charge of a squadron). He was involved in a number of key battles, including the Battle of Konzer Brucke outside Trier in which the horses he was riding were killed three times. Before the end of the war his father called for his return in order to name him successor to the duchy and remove him from subsequent danger.
Frederick Augustus married Countess Albertine Sophie Esther on 9 February 1679, the last remaining member of the counts of Eberstein (now known as Alt-Eberstein). This brought ownership of the Kraichgau towns such as Gochsheim, Waldangelloch and properties along the border to Lorraine. The newly weds had Gochsheim Castle renovated and used it as their residence from 1682 onwards.