The Vatatzes or Batatzes (Greek: Βατάτζης) family was a noble Byzantine family of the 11th–14th centuries, which produced several senior generals of the Byzantine army and, after John III Doukas Vatatzes intermarried with the Laskaris, the ruling line of the Empire of Nicaea until the usurpation of Michael VIII Palaiologos in 1261. The feminine form of the name is Vatatzina (Βατατζίνα).
The first member of the family, known simply by his surname, is attested around the year 1000. John Skylitzes (Synopsis Historion, 343.134) records that "Vatatzes with his entire family" was among those "distinguished citizens of Adrianople" who fled to the Bulgarian emperor Samuel because they were accused of pro-Bulgarian sentiments. Over the next centuries, the family remained associated with Adrianople and the surrounding region (the thema of Macedonia), where their estates were.
In 1047, a John Vatatzes joined the revolt of Leo Tornikios, but in the 12th century they rose to high offices: Theodore Vatatzes was named despotes by Emperor Manuel I, and his son John Komnenos Vatatzes became megas domestikos (commander-in-chief of the Byzantine army). Another Vatatzes, Nikephoros, was domestikos of the West, and Basil Vatatzes was domestikos of the East soon after. Basil was possibly the father of John III Doukas Vatatzes (reigned 1221–1254) and his brother, the sebastokrator Isaac Doukas Vatatzes.
John III was succeeded as Emperor of Nicaea by his son Theodore II (r. 1254–1258), who however preferred his mother's surname, Laskaris. Theodore II's son, John IV Laskaris (r. 1258–1261), was driven from the throne by Michael VIII Palaiologos (r. 1259–1282), but the family remained important. The last prominent member was John Vatatzes in the mid-14th century.
A variant of the family name, Diplovatatzes (Διπλοβατάτζης, "Double Vatatzes"), was used from the mid-12th century on for family members who descended from the Vatatzai on both sides. They too ranked among the senior nobility of the late Byzantine Empire.
- Kazhdan (1991), pp. 2154–2155
- Wortley (2010), p. 325
- Kazhdan, Alexander (1991). Kazhdan, Alexander, ed. Oxford Dictionary of Byzantium. New York, New York and Oxford, United Kingdom: Oxford University Press. pp. 2154–2155. ISBN 978-0-19-504652-6.
- Wortley, John, ed. (2010), John Skylitzes: A Synopsis of Byzantine History, 811-1057, Cambridge, United Kingdom: Cambridge University Press, ISBN 978-0-521-76705-7