The following three new species of Trypetheliaceae are described from Sri Lanka: Astrothelium inspersoconicum, A. isohypocrellinum, and Polymeridium fernandoi. Ten species are newly recorded from Sri Lanka: Astrothelium flavoduplex, A. galligenum, A. scoria, A. straminicolor, Constrictolumina planorbis, C. porospora, Dictyomeridium proponens, Marcelaria cumingii, Polymeridium jordanii, and Pseudopyrenula media. Keywords: Astrothelium / Constrictolumina / corticolous / Dictyomeridium / lichens / Marcelaria / Polymeridium / Pseudopyrenula.