• Najas Hübner, 1807 (uncertain) [Family: Lepidoptera (awaiting allocation)]
• Najas Linnaeus, 1753 [Family: Hydrocharitaceae]
• Najas ancistrocarpa auct. non Magnus accepted as Najas filifolia Haynes
• Najas caespitosa (Maguire) Reveal accepted as Najas flexilis (Willd.) Rostk. & Schmidt
• Najas conferta (A. Braun) A. Braun accepted as Najas wrightiana A. Braun
• Najas filifolia Haynes
• Najas flexilis (Willd.) Rostk. & Schmidt
• Najas gracilis (Morong) Small accepted as Najas marina L.
• Najas gracillima (A. Braun ex Engelm.) Magnus
• Najas graminea Delile
• Najas guadalupensis (Spreng.) Magnus
• Najas major All. accepted as Najas marina L.
• Najas marina L.
• Najas minor All.
• Najas muenscheri Clausen accepted as Najas guadalupensis (Spreng.) Magnus
• Najas olivacea Rosendahl & Butters accepted as Najas guadalupensis (Spreng.) Magnus
• Najas wrightiana A. Braun
• Najash Apesteguía & Zaher, 2006 †