The chapter discusses executive functions (EFs), which are mental processes essential for concentration, attention, and decision-making. Core EFs include inhibition (response inhibition and interference control), working memory (WM), and cognitive flexibility. Inhibition involves controlling attention, behavior, thoughts, and emotions to override strong internal or external influences. WM involves holding and manipulating information in mind, while cognitive flexibility allows for creative thinking and adapting to new situations. The chapter explores the developmental progression of these EFs, representative measures, and controversies surrounding their relationship with other cognitive abilities. It also highlights the importance of social, emotional, and physical health in maintaining cognitive health and the potential for EFs to be improved through practice.The chapter discusses executive functions (EFs), which are mental processes essential for concentration, attention, and decision-making. Core EFs include inhibition (response inhibition and interference control), working memory (WM), and cognitive flexibility. Inhibition involves controlling attention, behavior, thoughts, and emotions to override strong internal or external influences. WM involves holding and manipulating information in mind, while cognitive flexibility allows for creative thinking and adapting to new situations. The chapter explores the developmental progression of these EFs, representative measures, and controversies surrounding their relationship with other cognitive abilities. It also highlights the importance of social, emotional, and physical health in maintaining cognitive health and the potential for EFs to be improved through practice.