Velcro is a brand name for a type of loop and hook fastening technology which is used in an extremely wide range of applications. Velcro was the first of such loop and hook fasteners to be created so the name has become synonymous with the technology, even though technically Velcro is brand.

The technology behind Velcro is essentially the same that is used by many plants in the spread of their seeds. Some plant seeds are encased in shells with hook like burrs, or spines that can cling to animal fur or clothing. Velcro works by joining two panels of material, one with a surface of fairly rigid plastic hooks, and one with as surface of thinner wispy loops of plastic that the hooks will cling to when the panels are pressed up against reach other. When the panels are pressed together, the Velcro will hold in place fairly firmly, unless the panels are pealed back from one another. This allows for quick and secure fastening and release. Velcro is commonly used for children's shoes, who may not know how to tie them, and as straps on various devices such as backpacks, life vests, luggage, and joint braces. Hook and loop fasteners have evolved into a fairly ubiquitous technology.

One of the biggest advantages of Velcro over other fastening technologies is the ease of fastening and removal. All that one needs to do to fasten Velcro is to press the hook panel surface against the loop panel surface. To remove it, one simply pulls back on the surfaces to rip them apart. Not only does this mean fastening and removal of Velcro is faster than that of buttons, zippers, or snaps, it can also be refastened more easily during use. For instance, if a jogger has an armband fastened with Velcro, he could easily undo it, and refasten it, without stopping. This also makes Velcro easy for children to use. While the bonding strength of Velcro does not decline much from repeated use, the hooks can grab onto and collect things like hair, fuzz and lint, which can reduce Velcro's effectiveness over time. Also, the hooked surface can grab onto materials other than the looped surface, which can cause damage to the other material in some cases. Also, the tearing noise that Velcro makes can be a disadvantage in circumstances where one wants to stay quiet but must unfasten something.