Lung cancer is the leading cause of cancer-related mortality globally, primarily due to late-stage diagnosis. There is a paramount need for rapid, non-invasive diagnostic tools. MicroRNAs (miRNAs) have emerged as ideal circulating biomarkers for early detection, but their clinical translation has been hindered by the limitations of conventional detection methods. The recent convergence of miRNA biology with CRISPR-Cas biosensing technology is poised to overcome these barriers. This review synthesizes advancements in CRISPR-based biosensors for detecting lung cancer miRNA biomarkers. We begin by outlining the landscape of lung cancer-associated miRNAs and the clinical validity of miRNA signatures from liquid biopsies. The core of the review critically examines the CRISPR-Cas biosensing architecture, focusing on the distinct mechanisms of Cas13 and Cas12a systems engineered for miRNA detection. We further explore engineering strategies that augment performance, including integration with isothermal amplification and various signal transduction methods. A critical appraisal reveals that these platforms consistently achieve exceptional sensitivity and single-base specificity in detecting targets like miR-21 in clinical samples. Finally, we address prevailing challenges, such as off-target effects and reagent stability, and outline promising future directions, including multiplexed detection, integration with multi-analyte liquid biopsy platforms, and the development of fully automated, handheld devices. We conclude that CRISPR-based miRNA biosensors represent a transformative diagnostic paradigm with immense potential to enable rapid, precise, and accessible early detection of lung cancer, thereby paving the way for improved survival rates.