A standoff is a mechanical device for holding a printed circuit board (PCB) firmly in physical connection with a mechanical chassis or to another PCB board. They are available in a variety of materials but are principally categorized as insulating plastic or conductive metallic standoffs.

Standoffs can be 'threaded' or 'unthreaded'. Unthreaded standoffs usually press an expanding end through the PCB or mechanical structure (self-retaining). Threaded standoffs usually have hexagonal female ends to allow them to be screwed in and also screwed into each other. They can usually also be screwed into by a bolt and in these cases, the PCB or mechanical structure is sandwiched between the bolt and the standoff, using washers to prevent damage or stress to components.

Standoffs are also available as round rod-like members that can be screwed into things and be screwed into accordingly. Standoffs can be screwed into each other to increase heights. Important characteristics of standoffs include the 'overall length', 'between board height', 'outside diameter', 'inside diameter' and 'thread size'. There are special hinged standoffs, and standoffs that have vibration damping characteristics. Materials include the previously indicated metals and plastics, but can also be other materials like ceramics, resins, and stainless steel.