Graphidaceae is one of the largest families of lichenized fungi, with over 2,300 species in 80 genera known and about 3,600 species predicted. The Eastern Paleotropics constitute one of the hotspots of Graphidaceae diversity, including many potentially unknown species awaiting discovery. The Malaysian state of Sabah in NE-Borneo is home to some of the oldest continuously forested areas in SE-Asia, but only a few recent studies sampled Graphidaceae, particularly in the remaining pockets of lowland Dipterocarp forests. As part of two larger field trips in 2012 and 2013, hundreds of specimens of mostly epiphytic Graphidaceae were collected. The identification of 115 collections thus far has resulted in 52 species, all of which represent new records for this region, including eight species new to science in eight different genera (Allographa, Astrochapsa, Byssotrema, Diorygma, Melanotrema, Ocellularia, Platythecium, Sarcographa), as well as new records for the Eastern Paleotropics, Malaysia, and Borneo. Most of the new species were found in old growth forests, and very few in selectively logged forests, highlighting the importance of effective conservation by strict protection of the remnants of unlogged stands for the highly threatened lowland Dipterocarp forests in SE-Asia. Key words: Acanthothecis, Heiomasia, muriform.