Thaxterogaster occidentalis is a species of fungus in the family Cortinariaceae.

[2] It was described in 1939 by the American mycologist Alexander H. Smith who classified it as Cortinarius occidentalis.

[2] In 2022 the species was transferred from Cortinarius and reclassified as Thaxterogaster occidentalis based on genomic data.

[3] Native to the Northern Hemisphere.