HAGLR Opposite Strand lncRNA (HAGLROS) is a long non-coding RNA (lncRNA) located on the long arm of human chromosome 2 at locus 2q31.1. Emerging evidence highlights HAGLROS as a pivotal player in human cancers, characterized by its significant upregulation across multiple malignancies where it functions as an oncogenic driver. Its aberrant expression is closely linked to the initiation and progression of 13 distinct cancer types, notably correlating with adverse clinical outcomes and reduced overall survival rates in 9 of these cancer types. Mechanistically, HAGLROS is under the regulatory influence of the transcription factor STAT3, exerts competitive binding to 9 miRNAs, activates 5 signaling pathways pivotal for cancer cell proliferation and metastasis, as well as intricately modulates gene expression profiles. Given its multifaceted roles, HAGLROS emerges as a promising candidate for cancer diagnostics and prognostics. Moreover, its potential as a therapeutic target holds considerable promise for novel treatment strategies in oncology. This review synthesizes current research on HAGLROS, covering its expression patterns, biological roles, and clinical significance in cancer. By shedding light on these aspects, this review aims to contribute new perspectives that advance our understanding of cancer biology, enhance diagnostic accuracy, refine prognostic assessments, and pave the way for targeted therapeutic interventions.