* ''Dendrobium aberrans'' – Deviating Dendrobium
* ''Dendrobium acaciifolium'' J.J.Sm.
* ''Dendrobium acanthophippiiflorum'' J.J.Sm.
* ''Dendrobium acerosum''
* ''Dendrobium acianthum''
* ''Dendrobium aciculare''
* ''Dendrobium acinaciforme'' – Saber-shaped Dendrobium
* ''Dendrobium aclinia''
* ''Dendrobium acuminatissimum''
* ''Dendrobium acutifolium''
* ''Dendrobium acutilobum''
* ''Dendrobium acutimentum''
* ''Dendrobium acutisepalum''
* ''Dendrobium adae'' – Ada's Dendrobium
* ''Dendrobium adamsii''
* ''Dendrobium aduncum'' – Inward-bent dendrobium, Angelfish orchid
* ''Dendrobium aemulum'' – Ironbark Orchid, Brush Box Orchid, White-feather Orchid, Similar-looking Dendrobium
*
* ''Dendrobium aemulum'' var. ''aemulum''
*
* ''Dendrobium aemulum'' var. ''callitrophilum''
* ''Dendrobium affine''
* ''Dendrobium agathodaemonis'' J.J.Sm.
* ''Dendrobium agrostophylloides''
* ''Dendrobium agrostophyllum'' – Grassy-leaved Dendrobium
* ''Dendrobium agusanense''
* ''Dendrobium alabense''
* ''Dendrobium alaticaulinum'' – Winged-stem Dendrobium
* ''Dendrobium albayense''
* ''Dendrobium albosanguineum'' – White and blood-red dendrobium
* ''Dendrobium alboviride''
* ''Dendrobium alderwereltianum''
* ''Dendrobium alexandrae'' – Alexandra's Dendrobium
* ''Dendrobium aliciae''
* ''Dendrobium aloefolium''
* ''Dendrobium alterum''
* ''Dendrobium alticola''
* ''Dendrobium amabile''
* ''Dendrobium amboinense''
* ''Dendrobium ambotiense''
* ''Dendrobium amethystoglossum'' – Amethyst-coloured Dendrobium
* ''Dendrobium amoenum'' – Lovely Dendrobium
* ''Dendrobium amphigenyum''
* ''Dendrobium anamalayanum''
* ''Dendrobium anceps'' – Double-edged Dendrobium
* ''Dendrobium × andersonianum''
* ''Dendrobium andreemillarae''
* ''Dendrobium angiense''
* ''Dendrobium angulatum''
* ''Dendrobium angustiflorum''
* ''Dendrobium angustipetalum''
* ''Dendrobium angustispathum''
* ''Dendrobium annae''
* ''Dendrobium annamense''
* ''Dendrobium annuligerum''
* ''Dendrobium anosmum'' – Unscented dendrobium
*
* ''Dendrobium anosmum'' var. ''Dearei'' or ''Alba''
*
* ''Dendrobium anosmum'' var. ''Huttonii''
*
* ''Dendrobium anosmum'' var. ''Semi-alba''
*
* ''Dendrobium anosmum'' var. ''Superbum''
* ''Dendrobium antennatum'' – Antelope orchid (sometimes separated in ''Ceratobium'')
* ''Dendrobium anthrene''
* ''Dendrobium apertum''
* ''Dendrobium aphanochilum''
* ''Dendrobium aphrodite'' – Aphrodite's Dendrobium
* ''Dendrobium aphyllum'' – Leafless dendrobium
* ''Dendrobium appendicula''
* ''Dendrobium aqueum''
* ''Dendrobium araneum''
* ''Dendrobium argiense''
* ''Dendrobium aridum''
* ''Dendrobium aries''
* ''Dendrobium aristiferum''
* ''Dendrobium armeniacum''
* ''Dendrobium armitiae''
* ''Dendrobium aromaticum''
* ''Dendrobium arthrobulbum''
* ''Dendrobium asperatum''
* ''Dendrobium asperifolium'' J.J.Sm.
* ''Dendrobium asphale''
* ''Dendrobium assamicum''
* ''Dendrobium atavus''
* ''Dendrobium atjehense''
* ''Dendrobium atromarginatum'' J.J.Sm.
* ''Dendrobium atropurpureum''
* ''Dendrobium atrorubens''
* ''Dendrobium atroviolaceum'' – Black blood-red dendrobium
* ''Dendrobium attenuatum''
* ''Dendrobium aurantiflammeum''
* ''Dendrobium aurantiroseum'' – Aunty Rosie
* ''Dendrobium auriculatum'' – Eared Dendrobium
* ''Dendrobium austrocaledonicum''
* ''Dendrobium auyongii''
* ''Dendrobium axillare''
* ''Dendrobium ayubii''