<p>Rain-induced slope failures pose a major hazard in natural and engineered environments, emphasizing the need for non-destructive techniques capable of capturing subsurface moisture dynamics. Infrared thermography has gained increasing attention, of late, as a remote sensing tool for the detection of thermal anomalies associated with water seepage and moisture accumulation along the slope, which act as precursors for slope failure. This review critically evaluates the application of Infrared thermography (IRT) in Geotechnical Engineering, especially in assessing landslides, with primary focus on passive field-based monitoring that exploits natural thermal contrast, thereby exhibiting its efficiency as a non-contact, non-destructive landslide monitoring technique. This paper synthesizes recent studies demonstrating the utility of thermographic methods in identifying early signs of landslides by capturing thermally induced signatures of moisture redistribution that govern rainfall-induced slope instability. Key methodological aspects such as the detection limits, variation of surface emissivity and atmospheric attenuation under rainy conditions are discussed. Further, the thermal image processing methodologies and data analysis procedures, such as Principal Component Analysis (PCA) and Structural Similarity Index Method (SSIM), are comprehensively explained. Finally, by summarizing existing research and identifying gaps, this review article aims to focus on the advantages and limitations of infrared thermography in landslide prediction and outline future directions of research in this emerging field.</p>