A taxonomic revision ofRhizophoraL. (Rhizophoraceae) in Thailand is presented. Two species,R. apiculataBlume andR. mucronataPoir., are enumerated with updated morphological descriptions, illustrations and a taxonomic identification key, together with notes on distributions, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. Three names inRhizophora, are lectotypified:R. apiculataand two associated synonyms ofR. mucronata(i.e.,R. latifoliaMiq. andR. macrorrhizaGriff.).R. longissimaBlanco, a synonym ofR. mucronata, is neotypified. All twoRhizophoraspecies have a conservation assessment of Least Concern (LC). Based on the morphological identification, these two species can be distinguished from one another by the shape and width of the leaf laminae and the length of a terminal stiff point of the leaf laminae; the type and position of the inflorescences and the number of flowers per inflorescence; the character and color of the bracteoles; the presence or absence of the flower pedicels; the shape of the mature flower buds; the shape, color, and texture of the sepals; the shape, character, and the presence or absence of hairs of the petals; the number of stamens per flower; the size of the fruits; the color and size of the hypocotyls; the color and diameter of the cotyledonous cylindrical tubes; and the color of the colleters and exudate. The thick cuticles, sunken stomata, large hypodermal cells, and cork warts are adaptive anatomical features of leaves inRhizophorathat live in the mangrove environments. The pollen grains of ThaiRhizophoraspecies are tricolporate, prolate spheroidal or oblate spheroidal shapes, small-sized, and reticulate exine sculpturing.