Wilhelm Aarstad (15 January 1854 – ??) was a Norwegian politician for the Liberal Left Party.
He was born at Aarstad in Egersund as a son of farmers.
He was a first cousin of Søren Tobias Årstad, and moved to Stavanger to be a merchant like Søren's side of the family.He was elected to Stavanger city council, and in 1909 to the Parliament of Norway as a deputy representative.
He was the running mate of Jonas Schanche Kielland, and met in his place in parliamentary session in both 1911 and 1912.