UVs Not Showing in Blender
The UV Editor is empty
Also known as: Blender UV editor empty · Blender UV not showing · Blender UV sync selection · Blender UV editor blank · Blender cannot see UV
Quick answer
The Blender UV Editor only shows the UVs of faces that are selected in Edit Mode. Press Tab to enter Edit Mode, press A to select everything, and the UV islands appear. If you want the editor to show UVs regardless of the selection, enable UV Sync Selection in the editor header. Make sure the object actually has a UV map in Object Data properties.
How to fix it
If you see UVs but cannot select them, check whether UV Sync Selection is on, because it changes how selection works. A mesh with no UV map needs one: add it in Object Data properties and unwrap with U in Edit Mode. When UVs overlap after unwrapping, pack the islands and give them margin. Use the Stretch overlay and a checker texture to check distortion.