An edge trimmer or lawn edger is a garden tool, either manual or motorised, to form distinct boundaries between a lawn, typically consisting of a grass, or other soft botanical ground cover, and another ground surface feature such as a paved, concreted or asphalted area, or a granular material such as sand or gravel, or simply uncovered soil, for example an unbounded garden.

There are six main types of lawn edger:

• Manual
  • Spade-based
  • Roller-based
  • Hand shears
• Motorised
  • Adaptable string trimmer
  • Single-wheel purpose-designed
  • Multi-wheel purpose-designed

Purpose-designed lawn edgers are more time efficient for long and even edges, while string trimmers are more efficient for angular edges and around interrupting features such as rocks. Spade based, roller based, and adaptable string trimmer designs may all be known as stick trimmers.

Typical situations for the use of lawn edgers are to define clean boundaries, and stop grass incursion, between lawns and walkways or gardens in private properties and public areas, and between sand traps and greens or fairways on golf courses.