More than 25 years have passed since Ancel Keys and others observed that high intake of monounsaturated fatty acids, especially as supplied by plants (eg, olive oil) was associated with lower cardiovascular and overall mortality. About 15 years later, advances in genotyping technologies began to facilitate widespread study of relationships between dietary fats and genetic variants, illuminating the role of genetic variation in modulating human responses to fatty acids. More recently, microarray technologies evaluate the ways in which minor, bioactive compounds in plant oils (including olive, thyme, lemongrass, clove, eucalyptus, and others) alter gene expression to mediate anti-inflammatory and antioxidant effects. Results from a range of diverse technologies and approaches are coalescing to improve understanding of the role of the genome in shaping our responses to plant oils, and to clarify the genetic mechanisms underlying the cardioprotective benefits we derive from a wide range of plant oil constituents.