Ptychoderidae is a family of acorn worms.

The World Register of Marine Species lists the following:^[1]

Contains the following species:

• Balanoglossus apertus (Spengel, 1893)
• Balanoglossus aurantiacus (Girard, 1853)
• Balanoglossus australiensis (Hill, 1894)
• Balanoglossus borealis (Willey, 1899)
• Balanoglossus capensis (Gilchrist, 1908)
• Balanoglossus carnosus Müller in Spengel, 1893
• Balanoglossus clavigerus delle Chiaje, 1829
• Balanoglossus gigas Müller in Spengel, 1893
• Balanoglossus hydrocephalus van der Horst
• Balanoglossus misakiensis Kuwano, 1902
• Balanoglossus natalensis (Gilchrist, 1908)
• Balanoglossus occidentalis Ritter, 1902
• Balanoglossus proterogonius Belichov, 1928
• Balanoglossus robinii author unknown
• Balanoglossus salmoneus Belichov, 1928
• Balanoglossus stephensoni van der Horst, 1937
• Balanoglossus studiosorum van der Horst

Contains the following species:

• Glossobalanus alatus van der Horst
• Glossobalanus barnharti Cameron & Ostiguy, 2013^[2]
• Glossobalanus berkeleyi (Willey, 1931)
• Glossobalanus crozieri van der Horst, 1924
• Glossobalanus elongatus Spengel, 1904
• Glossobalanus hartmanae Cameron & Ostiguy, 2013^[2]
• Glossobalanus hedleyi (Hill, 1897)
• Glossobalanus indicus Rao, 1955
• Glossobalanus marginatus Meek, 1922
• Glossobalanus minutus Kowalevsky, 1866
• Glossobalanus mortenseni van der Horst, 1932
• Glossobalanus parvulus (Punnett, 1906)
• Glossobalanus ruficollis (Willey, 1899)
• Glossobalanus sarniensis (Koehler, 1886)
• Glossobalanus williami Cameron & Ostiguy, 2013^[2]

Contains the following species:

• Ptychodera bahamensis Spengel, 1893
• Ptychodera ceylonica author unknown
• Ptychodera erythrea Spengel
• Ptychodera flava Eschscholtz, 1825
• Ptychodera pelsarti Dakin, 1916