The House of Pejačević or Pejácsevich[a][b] is an old Croatian noble family, remarkable during the period in history marked by the Ottoman war in the Kingdom of Croatia and Austro-Hungarian Empire respectively.

Notable members of the family were politicians, clerics, artists, senior military officers, Bans (viceroys) of Croatia and other high state officials.

The 59th volume of the "Archive for the Austrian History" issued by the Imperial Academy of Sciences in Vienna in 1880 includes a long chapter about Baron Petar Parčević (1612–1674), the archbishop of Marcianople, a town in eastern Bulgaria.

The branches of Parchevich family lived not only in Chiprovtsi, but also in the neighboring villages, even founding some new ones, like Kneže (Knezhe), Pejakovo or Pejačevo (Pe'yachevo) and Čerka (Cherka).

The author has written that the catholic Franciscans had arrived from medieval Bosnia in western Bulgaria at the time of Bosnian vicar Bartul Alvernski (Bartholomew of Alverno), who himself originated from Italy, in 1366.

Contact between the ancestors of the Pejačević family and members of the Franciscan order must have been started at the very beginning, but they were intensified by the end of the 16th century, when the Catholic enclave in Chiprovtsi was visited by missionaries sent by the pope.

It is indisputable that a great deal of Bulgarian Catholics, especially those in the Chiprovtsi enclave and its surroundings, originated from medieval Croatian and Bosnian territory, and particularly from the Republic of Ragusa (present-day Dubrovnik).

The Habsburg imperial army, supported by some European states, penetrated deep into the Ottoman territory in south-eastern Europe, which encouraged the Chiprovtsi Catholics in 1688 to rise up against the occupiers in order to free Bulgaria.

After heavy fighting, the Ottomans managed to suppress the uprising by the end of 1688 and destroyed Chiprovtsi and neighboring villages like Klisura, Zhelezna and Kopilovtsi.

The surviving inhabitants, including Đuro's brothers Marko II (Mark), Ivan (John) and probably Nikola (Nicholas), together with their families, fled to the north, until they reached the Habsburg controlled territories.

Pejačevićs were one of the Catholic families from Chiprovtsi in Bulgaria that moved, most probably through Wallachia and Transilvania, to the Hungarian town of Pécs and soon after that to Osijek in Slavonia, a northeastern Croatian province, in the Kingdom of Hungary.

Josip Bösendorfer, PhD, Croatian historian, wrote in the scientific journal "Narodna starina" (English: Folk Art Antiquities), published in 1932 in Zagreb: Those Chiprovtsians came to Osijek from Pecs, because they escaped from Rákóczi's uprising.

On June 10, 1712, the Holy Roman Emperor and the Croato-Hungarian King Charles III of Habsburg acknowledged the Pejačević brothers as Barons on behalf of the old title their ancestors received in Bulgaria.

While some family members stayed in Osijek (e.g. brothers Marko II (1664–1727) and Ivan (1666–1724)), the others settled in Srijem and Bačka, two provinces at the frontier of Croatia.

In the meantime (1747), a part of Mitrovica's demesne land had been included into the Military Frontier, so Marko III Aleksandar was given the right to buy Virovitica and Retfala estates.

On August 29, 1749, the Holy Roman Empress and the Croato-Hungarian Queen Maria Theresa of Habsburg-Lothringen granted the Virovitica estate to Baron Marko III Aleksandar Pejačević, and it became the most significant property of the family in the second half of the 18th century.

By the end of 18th and the beginning of 19th century he started with preparations for construction of a new castle in Našice, with the support of his son Vincencije Ljudevit (Vincent Louis; 1780–1820).

On July 22, 1772, the Holy Roman Empress and the Croato-Hungarian Queen Maria Theresa of Austria gave him the title of hereditary count, and since then the whole family carries the full name "Pejačević of Virovitica".

Josip was succeeded in Virovitica by his youngest son Antun, a Habsburg imperial army lieutenant field marshal with an outstanding military career.

In his will, dated September 15, 1780, count Josip II Pejačević left his estates Ruma and Retfala to his eldest son Žigmund (1741–1806), who established the Ruma-Retfala branch of the family.

At the beginning of the 20th century, he was faced with a new direction of Croatian policy marked by political alliance between Croats and Serbs in Austria-Hungary for mutual benefit.

The surviving members of the family emigrated from the Eastern Bloc to countries like Austria, Switzerland, Italy, France, Germany, Great Britain, Spain, Argentina, Uruguay, Colombia, Venezuela, and the US, where some of their relatives already had lived before.

Marcos Pejacsevich (Osijek, 1940-), entrepreneur, president of the Argentine–Croatian Chamber of Industry and Commerce, and current head of the Argentinean branch of the family is the younger son of Petar.

The former German Minister of Defence, Karl-Theodor zu Guttenberg, is a descendant of this family, through Ludwine, Countess Pejacsevich de Verocze, married to Jakob, Count of Eltz.