Lactose intolerance (LI) is a condition in which the consumption of lactose-containing products leads to gastrointestinal symptoms. Despite being a common digestive disorder worldwide, LI is often overlooked, and there are few established recommendations for its diagnosis and management. This review aims to provide a comprehensive overview of LI, focusing on its clinical features, diagnostic evaluation, and management strategies. A review of literature published from 2013 to 2023 on PubMed was conducted. Systematic reviews, meta-analyses, randomized controlled trials, case-control studies, cohort studies, and expert reviews were prioritized for analysis. LI is a common condition that shares symptoms with several other diseases. Various diagnostic tests are available to identify LI, including hydrogen breath test (HBT), lactose tolerance test, urinary galactose test, gaxilose test, rapid lactase test, and genetic testing. Managing LI may involve adopting a lactose-free or low-lactose diet, taking oral enzyme supplements, using probiotics and prebiotics, or consuming plant-based alternative beverages. LI affects many people worldwide and can significantly impact their quality of life. The HBT is the most widely used and effective method for diagnosing LI, along with a thorough assessment of symptoms. Instead of following a completely dairy-free diet, adopting a low-lactose diet - allowing up to 12-15 g of lactose per day - has been shown to be well tolerated and beneficial for most individuals with LI. While probiotics, prebiotics, and plant-based beverages may be helpful, their effectiveness in managing LI has not yet been proven.