Linseed oil, derived from the Linum usitatissimum plant of the Linaceae family, is renowned for its extraordinary composition, earning it a distinguished place among superfoods. It is a plant-based source rich in polyunsaturated fatty acids (PUFA), especially α-linolenic acid (ALA), which is an indispensable nutrient for maintaining optimal health. The unique fatty acid profile of linseed oil supports cardiovascular and brain health and contributes to cellular structure and function. Beyond its fatty acids, linseed oil is also a reservoir of minor phytonutrients such as vitamin E, phospholipids, phytosterols, polyphenols, lignin, and squalene, collectively referred to as concomitant substances. These compounds not only promulgate the health benefits of linseed oil but also contribute to its stability and functional properties. The composition and stability of linseed oil are influenced by various geographical and genetic factors, which directly or indirectly influence its yield and fatty acid composition, particularly the ALA content. In contrast, other minor constituents are less affected by environmental factors. Understanding the major and minor constituents of linseed oil provides valuable insights into the oil’s potential to promote general health and well-being and pave the way to explore its diverse applications in food industries.