ADP-ribosylation factor-like protein (ARL) family members (ARLs) may regulate the malignant phenotypes of cancer cells. However, relevant studies on ARLs in breast cancer (BC) are limited. In this research, the expression profiles, genetic variations, and prognostic values of ARLs in BC have been systematically analyzed for the first time using various databases. We find that ARLs are significantly dysregulated in BC according to the TCGA database, which may result from DNA methylation and copy number alteration. Prognostic analysis suggests that ARL11 is the most significant prognostic indicator for BC, and higher ARL11 predicts worse clinical outcomes for BC patients. Further functional enrichment analysis demonstrates that ARL11 enhances the immunosuppression in BC, and dysregulation of ARL11 is significantly associated with immune infiltration in various types of cancer. Our results demonstrate the potential of ARL11 as an immune therapeutic target for BC.