Crossocerus is a genus of square-headed wasps in the family Crabronidae. There are at least 250 described species in Crossocerus.

European species: Species within this genus include:

• Crossocerus acanthophorus (Kohl 1892)
• Crossocerus adhaesus (Kohl 1915)
• Crossocerus annulipes (Lepeletier & Brulle 1835)
• Crossocerus assimilis (F. Smith 1856)
• Crossocerus barbipes (Dahlbom 1845)
• Crossocerus binotatus Lepeletier & Brulle 1835
• Crossocerus capitosus (Shuckard 1837)
• Crossocerus cetratus (Shuckard 1837)
• Crossocerus cinxius (Dahlbom 1838)
• Crossocerus congener (Dahlbom 1844)
• Crossocerus denticoxa (Bischoff 1932)
• Crossocerus denticrus Herrich-Schaeffer 1841
• Crossocerus dimidiatus (Fabricius 1781)
• Crossocerus distinguendus (A. Morawitz 1866)
• Crossocerus elongatulus (Vander Linden 1829)
• Crossocerus exiguus (Vander Linden 1829)
• Crossocerus guichardi Leclercq 1972
• Crossocerus heydeni Kohl 1880
• Crossocerus italicus Beaumont 1959
• Crossocerus leucostoma (Linnaeus 1758)
• Crossocerus lindbergi (Beaumont 1954)
• Crossocerus lundbladi (Kjellander 1954)
• Crossocerus megacephalus (Rossi 1790)
• Crossocerus nigrita (Lepeletier & Brulle 1835)
• Crossocerus ovalis Lepeletier & Brulle 1835
• Crossocerus palmipes (Linnaeus 1767)
• Crossocerus podagricus (Vander Linden 1829)
• Crossocerus pullulus (A. Morawitz 1866)
• Crossocerus quadrimaculatus (Fabricius 1793)
• Crossocerus styrius (Kohl 1892)
• Crossocerus subulatus (Dahlbom 1845)
• Crossocerus tarsatus (Shuckard 1837)
• Crossocerus toledensis Leclercq 1971
• Crossocerus vagabundus (Panzer 1798)
• Crossocerus varus Lepeletier & Brulle 1835
• Crossocerus walkeri (Shuckard 1837)
• Crossocerus wesmaeli (Vander Linden 1829)