"Do it yourself" ("DIY") is the method of building, modifying, or repairing things by oneself without the direct aid of professionals or certified experts. Academic research has described DIY as behaviors where "individuals use raw and semi-raw materials and parts to produce, transform, or reconstruct material possessions, including those drawn from the natural environment (e.g., landscaping)". DIY behavior can be triggered by various motivations previously categorized as marketplace motivations (economic benefits, lack of product availability, lack of product quality, need for customization), and identity enhancement (craftsmanship, empowerment, community seeking, uniqueness).

The term "do-it-yourself" has been associated with consumers since at least 1912 primarily in the domain of home improvement and maintenance activities. The phrase "do it yourself" had come into common usage (in standard English) by the 1950s, in reference to the emergence of a trend of people undertaking home improvement and various other small craft and construction projects as both a creative-recreational and cost-saving activity.

Subsequently, the term DIY has taken on a broader meaning that covers a wide range of skill sets. DIY has been described as a "self-made-culture"; one of designing, creating, customizing and repairing items or things without any special training. DIY has grown to become a social concept with people sharing ideas, designs, techniques, methods and finished projects with one another either online or in person.

DIY can be seen as a cultural reaction in modern technological society to increasing academic specialization and economic specialization which brings people into contact with only a tiny focus area within the larger context, positioning DIY as a venue for holistic engagement. DIY ethic is the ethic of self-sufficiency through completing tasks without the aid of a paid expert. The DIY ethic promotes the idea that anyone is capable of performing a variety of tasks rather than relying on paid specialists.