No fewer than 20 belts of mafic-ultramafic assemblages have been named “ophiolite” in the complex Southeast Asia region of Sundaland. Fewer than half of these can be confidently classified as ophiolite. The only well-documented complete ophiolite, with continuous conformable sections from mantle harzburgite through gabbro to spilite, occurs in northeast Borneo and the neighboring Philippine Islands. It contains a record of oceanic lithospheric history from Jurassic to Tertiary and has a Miocene emplacement age. All other ophiolite belts of the region are either incomplete or dismembered. The Sundaland region probably has examples of several types of emplacement mechanism and emplacement ages ranging from early Paleozoic to Cenozoic.