Begonia sect. Diploclinium (Begoniaceae) is revised for the Philippine island of Palawan. Five new species, Begonia acclivis C.Coyle, B. cleopatrae C.Coyle, B. gutierrezii C.Coyle, B. rubiteae M.Hughes and B. wilkiei C.Coyle, are described, giving a total of 10 species, nine of which are endemic. Of the 10 species, two are considered to belong to the IUCN category Endangered, five are Vulnerable, two are Least Concern and one is Data Deficient.