The blunt‐nosed leopard lizard (BNLL; Gambelia sila) is an endangered species endemic to the San Joaquin Desert of California. Understanding its diet is fundamental to the conservation of the species and its habitat. A number of populations, including that of the Panoche Plateau, have undergone or are in the process of becoming extinct, which underscores the urgency of obtaining fundamental ecological data. DNA metabarcoding leverages the power of high-throughput DNA sequencing to provide both higher taxonomic resolution and prey-detection capacity over traditional fecal diet analyses. We collected fecal samples from across the range during 2013-2021 and used DNA metabarcoding to recover arthropod diet sequences. Based on data from >700 fecal samples we identified >100 invertebrate diet items. Orthopterans (grasshoppers etc.), Hemipterans (true bugs), and Coleopterans (beetles) were the most abundant orders in the BNLL diet across sites. However, the abundance of individual diet species varied widely even among contemporaneous samples. The Panoche Plateau population appeared to have the lowest diet diversity across all sites examined. This population was considered functionally extinct by 2022. The highly resolved arthropod diet data from this study will also improve our ability to assess sites for BNLL suitability.