Ostrau may refer to the following places:

• Ostrau, Mittelsachsen, a municipality in the district Mittelsachsen, Saxony, Germany
• Ostrau (Bad Dürrenberg), a village in Bad Dürrenberg in the Saalekreis district, Saxony-Anhalt, Germany
• Ostrau (Elsteraue), a village in Elsteraue in the Burgenlandkreis, Saxony-Anhalt, Germany
• Ostrau (Petersberg), a village and former municipality in the Saalekreis district, Saxony-Anhalt, Germany
• Ostrau (Grimma), a part of Grimma in the district Landkreis Leipzig, Saxony, Germany
• Ostrau (Bad Schandau), a village in Bad Schandau municipality, Saxony, Germany
• the German name for Ostrava, Czech Republic