A description of the xylem anatomy of the genera Archytaea, Ploiarium, Bonnetia, Neblinaria, Neotatea, Caraipa, Haploclathra, Mahurea, Marila, Kielmeyera, and Asteropeia is given. All these genera except Asteropeia, were included in the family of the Bonnetiaceae by Maguire (1972). He considered the position of Asteropeia to be a doubtful one. Wood anatomy indicates that the genera Archytaea, Ploiarium, Bonnetia, Neblinaria, and Neotatea form a homogeneous group, which differs markedly from the Theaceae, as is concluded from comparisons with representatives of all groups of that family. The taxonomic position of the genera Caraipa, Haploclathra, Mahurea, Marila, and Kielmeyera, formerly referred to the Guttiferae, is discussed. The genera Caraipa and Haploclathra are wood anatomically similar to the other genera of the Bonnetiaceae; the genera Mahurea and Marila less so. Kielmeyera fits wood anatomically better in the Guttiferae than in the Bonnetiaceae. These conclusions are based on comparisons with all tribes of the Guttiferae. Asteropeia does not fit in with the Theaceae or Bonnetiaceae, and its wood anatomy supports the family status for this genus. Poeciloneuron is wood anatomically similar to the Bonnetiaceae. The taxonomic position of Pelliciera and of the Tetrameristaceae, in Melchior’s concept (1964) belonging to the Theaceae, is also considered. A general wood anatomical description of the Bonnetiaceae excluding Kielmeyera and Asteropeia concludes this paper. Bonnetiaceae are wood anatomically intermediate between Theaceae and Guttiferae.