Four new orchid species from Madagascar are described and illustrated. Notes on the distribution, ecology, and conservation status are provided. Bulbophyllum uroplatoides Hermans & G. A. Fischer, B. histrionicum Reichenbach f. ex G. A. Fischer & P. J. Cribb, and B. senghasii G. A. Fischer & Sieder belong to section Calamaria Schlechter, whereas B. bryophytoides G. A. Fischer & Andriantiana belongs to section Lichenophylax Schlechter. Bulbophyllum uroplatoides Hermans & G. A. Fischer is related to B. cardiobulbum Bosser, but differs in the thickened racemes, overall plant size, the shape of the sepals, petals, and lip, and coloration. Bulbophyllum histrionicum Reichenbach f. ex G. A. Fischer & P. J. Cribb was previously recognized by Reichenbach as a new species, but was never formally described. It is characterized by its large, orbicular to somewhat ovoid pseudobulbs that are green flushed with red, large, ovate-oblong to ovate-lanceolate leaves, red floral bracts, long sepals, narrowly triangular petals, and glabrous lip. Bulbophyllum senghasii G. A. Fischer & Sieder has orbicular, non-compressed bifoliate pseudobulbs, flowers with greenish yellow sepals that are spotted with dark brown on the outside, and an elliptic lip that is not compressed in the middle and has erose rather than long-ciliate margins and falcate rather than straight stelidia. Bulbophyllum bryophytoides G. A. Fischer & Andriantiana is a very tiny plant distinguishable from other species of section Lichenophylax by its densely long-ciliate petals and its ciliate lip that lacks a median callus and has a glabrous surface.