Wellington Boots are a Muggle item. However, they appear to be in use by wizards as well, as several pairs can be found at The Burrow.
From the Story[]
Discovered in Book 2, Chapter 3, The Burrow, Moment 2, The Weasleys'[]
"Wellington boots are waterproof rubber boots. The Weasleys own several pairs which lie in a jumble around the front door. They are named after the first Duke of Wellington, who popularised their use."
On Pottermore[]
Click to go to Book 2, Chapter 3, The Burrow, Moment 2, The Weasleys'