Lateral raises mainly work the lateral (middle) deltoids on the sides of your shoulders, with help from a few supporting muscles like the front delts, rear delts, traps, and rotator cuff stabilizers.

What do lateral raises work?

When you do a lateral raise (lifting dumbbells or cables out to the side), the key movement is shoulder abduction—moving your arm away from your body.

The star of that motion is the lateral deltoid, which gives shoulders that wider, “capped” look.

Primary muscle:

  • Lateral (middle) deltoid – main driver of the lift, adds width and roundness to your shoulders.

Secondary / supporting muscles:

  • Anterior deltoid (front shoulder) – helps lift the arm, especially if you bring the weight slightly forward.
  • Posterior deltoid (rear shoulder) – helps stabilize the shoulder joint during the movement.
  • Upper trapezius – can kick in more if you shrug or go too heavy, helping elevate the shoulder.
  • Rotator cuff muscles – work to keep the shoulder stable while the arm moves.

Why people use lateral raises

Many lifters add lateral raises to their routine to:

  1. Build broader-looking shoulders and a stronger V-taper.
  1. Improve shoulder balance so pressing movements (like bench or overhead press) don’t dominate only the front delts.
  1. Isolate the lateral delts with relatively light weight and high control, which is joint‑friendly when done with good form.

Quick form cues (so they hit the right muscles)

To keep the focus on the lateral delts instead of just traps or momentum:

  • Slight bend in the elbows, then lift out to the sides until arms are about parallel to the floor.
  • Lead with your elbows, not your hands, and avoid swinging or using your legs to cheat the weight up.
  • Stop around shoulder height to avoid excessive stress on the shoulder joint and rotator cuff.

TL;DR: Lateral raises primarily work your lateral deltoids (side shoulders) and secondarily involve front delts, rear delts, traps, and rotator cuff, making them a go‑to move for wider, more defined shoulders.

Information gathered from public forums or data available on the internet and portrayed here.