This volume presents a revision of the Caloplaca saxicola group (Teloschistaceae, Ascomycetes) of the northern Hemisphere. The revision is based on the study of morphological and anatomical characteristics of approximately 650 specimens and their relevant type material. The specimens and type material studied are documented in drawings of microscopic structures and photos of thallus habit and apothecia. As a result of this revision, the following taxa are now part of the C. saxicola group: Caloplaca arnoldii (Wedd.) Zahlbr.; C. arnoldii subsp. clauzadeana Gaya; C. arnoldii subsp. nana Gaya; C. arnoldii subsp. obliterata Gaya; C. arnoldiiconfusa Gaya & Nav.-Ros.; C. biatorina (A. Massal.) J. Steiner; C. decipiens (Arnold) Blomb. & Forssell; C. pseudofulgensia Gaya & Nav.-Ros.; C. pusilla (A. Massal.) Zahlbr.; C. rouxii Gaya, Nav.-Ros. & Llimona; C. saxicola (Hoffm.) Nordin; and C. schistidii (Anzi) Zahlbr.