Lateral elbow pain is one of the most frequent and disabling conditions affecting the upper extremity, with a multifactorial etiology ranging from tendinopathies to ligamentous instability and intra-articular pathology. Clinical assessment remains the cornerstone of diagnosis, with specific provocative tests such as the Chair, Cozen, and Maudsley maneuvers being widely applied to detect epicondylar or tendon involvement. However, persistent or recurrent symptoms often indicate more complex disorders, including symptomatic minor instability of the lateral elbow (SMILE) and posterolateral rotatory instability (PLRI). These conditions result from progressive attenuation of the radial collateral ligament (R-LCL) and annular ligament, leading to radial head hypermobility, chondral damage, and secondary tendinopathy of the extensor carpi radialis brevis. Novel clinical tests (supination and anterolateral pain test (SALT), posterior elbow pain by palpation–extension the radio capitellar joint (PEPPER), pivot shift, and tabletop relocation) improve diagnostic sensitivity for these subtle instabilities. Imaging plays a critical role in confirming diagnosis and planning treatment: while magnetic resonance imaging (MRI) and magnetic resonance (MR) arthrography are gold standards for soft tissue evaluation, computed tomography (CT) arthrography provides high-resolution insights into ligament integrity and intra-articular lesions, especially in detecting SMILE. Management should be tailored to the underlying pathology, integrating conservative strategies with surgical approaches such as arthroscopic plication of the R-LCL when instability predominates. A comprehensive diagnostic algorithm combining clinical findings and advanced imaging can significantly improve patient outcomes.