She was the only child of Philipp II the Younger of Katzenelnbogen and Ottilie of Nassau-Dillenburg, daughter of Jan IV of Nassau. Her baptism took place one month after her father's death, on 22 March in Starkenburg Castle, near Darmstadt. Philipp II the Younger was in turn the eldest of the two sons of Count Philipp I of Katzenelnbogenthe Elder and his first wife, Anna of Württemberg. Shortly after Ottilie's uncle and last male member of the family, Eberhard of Katzenelnbogen was murdered, her grandfather Philipp I made an agreement with Frederick I, Elector Palatine, under which Ottilie was betrothed with the Elector's nephew Philip; however, when she reached a marriageable age in 1467, eleven years after the engagement, the groom refused to marry her due to personal reasons. Instead, and thanks to the intrigues of John II of Baden, Elector and Archbishop of Trier, she was engaged with his nephew Christoph, heir of Baden-Baden. The marriage contract was signed on 20 June 1468, and the formal wedding ceremony took place seven months later, on 30 January 1469 in the city of Koblenz as a part of double ceremony, because that day Christoph's sister Cimburga married with Count Engelbert II of Nassau-Dillenburg. Only two years later, before 13 January 1471, Ottilie of Nassau-Dillenburg, Dowager Hereditary Countess of Katzenelnbogen remarried, with Count Oswald of Thierstein and three years later, on 24 January 1474, Anna of Nassau-Dillenburg, Engelbert II's sister, married with Count Philipp I of Katzenelnbogen the Elder as her second wife. Ottilie's dowry was the highest of the Middle Ages ever introduced into the House of Baden. In addition to the Stadeck Castle with all his accessories were added further 48,000 longer-dated guilders. The total amount was of about 80,000 florins. The marriage between Ottilie and her husband is described as happy. They had 15 children between 1470 and 1493, of whom 13 reached adulthood:
After Ottilie's grandfather died in 1479, began a dispute with her aunt's husband, Henry III, Landgrave of Upper Hesse for her share in the Katzenelnbogen possessions, which were previously negotiated in Ottilie's marriage contract. After lengthy negotiations, was made a settlement between both parties, in which the Margrave of Baden-Baden received a sum of 4,000 florins in exchange of the formal renunciation of his wife's claims. When Ottilie's cousin William III, Landgrave of Hesse died in 1500, she received another 12,000 guilders as monetary compensation, so in March 1501 the House of Baden finally waived their claims over the County of Katzenelenbogen. Ottilie died on 15 August 1517 in Baden-Baden and was buried in the localCollegiate Church. Her bronze Epitaph shows an image of her with the coats of arms of Württemberg and Katzenelnbogen at her feet.
