Esico of Ballenstedt (died around 1060) is the top ancestor of the House of Ascania, i.e., he is the oldest member of the house known for certain. Little is known about him, but he is assumed to have been count of the Schwabengau and of the Harzgau with his seat at Ballenstedt. His father is sometimes assumed to have been called Adalbert (counted as Count Adalbert I), but there is no evidence for this. Esico is assumed to have inherited properties from Odo I, Margrave of the Saxon Ostmark, who may have been his maternal grandfather.
He was succeeded by his son Adalbert II, Count of Ballenstedt.