BackgroundmicroRNAs (miRNAs) are crucial regulators of various biological processes and molecular functions. Aberrant miRNA expression has been linked in many studies to neoplastic transformation. Among these miRNAs, dysregulation of miR-301b-5p was associated with different types of cancer including breast cancer. Although many research works have investigated the function of miR-301b in carcinogenesis, few have examined its expression, biological, and clinical implications in breast cancer. Methodswe examined the expression levels of miR-301b-5p in human cancerous breast tissue compared to normal breast controls using different bioinformatic tools and RT-qPCR analyses. Resultswe detected that miR-301b-5p was differentially expressed in cancerous breast tissue when compared to normal controls. MiR-301b-5p was detected to be upregulated in high-grade (Grade 3) and triple-negative breast cancers. A significant strong positive correlation was detected between miR-301b and Ki-67, the commonly used proliferative marker in breast cancer. Bioinformatics analyses using the KM plotter revealed that miR-301b has significant prognostic power in assessing the OS of patients with breast cancer. The study also identified many fundamental biological processes and regulatory pathways associated with the investigated miR-301b-related hub genes. Interestingly, the expression pattern and prognostic significance of PTEN, the top hub gene regulated by miR-301b, highlighted the prognostic significance of PTEN in breast cancer. ConclusionThe current study findings suggest the potential use of miR-301b-5p as a possible diagnostic and prognostic biomarker in breast cancer. Moreover, this study emphasized the clinical and biological relevance of miR-301b-5p in breast cancer.