A. nuda may refer to:

• Aaptos nuda, a sea sponge
• Achroosia nuda, a Brazilian moth
• Agrotis nuda, a synonym of Agrotis bilitura, commonly called the potato cutworm, a South American moth
• Alcadia nuda, a Cuban land snail
• Andrena nuda, commonly called the naked miner bee, a North American bee
• Anomoeotes nuda, an African moth
• Apostasia nuda, an orchid
• Astroboa nuda, a basket star
• Astrophytum nuda, a synonym of Astrophytum myriostigma, a Mexican cactus
• Avena nuda, commonly called the hulless oat or naked oat