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<i>Rickettsia</i> spp. are the second most common pathogens detected in <i>Ixodes ricinus</i> ticks in Austria after <i>Borrelia burgdorferi</i> sensu lato. Species belonging to the spotted fever group (SFG) are the causative agents for tick-borne rickettsiosis across the world. So far, only four SFG <i>Rickettsia</i> spp. were detected in Austria, namely <i>R. helvetica</i>, <i>R. raoultii</i>, <i>R. monacensis</i> and <i>R. slovaca</i>. Here, we describe the identification of a new SFG <i>Rickettsia</i> species detected in an <i>I. ricinus</i> tick. Sequencing of various rickettsial genes revealed a nucleotide sequence similarity of 99.6%, 98.5%, 97.3% and 98.5% to the <i>gltA</i>, <i>ompA</i>, <i>ompB</i>, and <i>sca4</i> genes, respectively, of known and validated species. Additionally, sequencing of the <i>htrA</i> gene and 23S-5S intergenic spacer region also only showed 99.6% and 99.2%, respectively, similarity to known species. Therefore, and in accordance with current criteria for <i>Rickettsia</i> species discrimination, we hereby describe a new species of the SFG with putative pathogenic potential. We propose the name “<i>Candidatus</i> Rickettsia thierseensis” based on the village Thiersee in the Austrian province of Tyrol, where the carrying tick was found.