Under the terms of the deal, Westeinde will maintain its well recognized named throughout Eastern Ontario and operate as a stand-alone division.
Aecon said the acquisition is in keeping with its national growth strategy and will strengthen its position in the Ottawa market.
Since it was incorporated in 1978 under the ownership of the Westeinde family, the company has grown into a $100-million a year business.
Westeinde and Aecon are already partners on a number of ventures, including a $43-million contract from Minto Developments Inc. awarded one year ago to build the Metropole condominium tower at 170 Lanark Ave.
"Westeinde has a strong and profitable foothold in the Ottawa market," John M. Beck, chairman and CEO of Aecon, said in a statement.
"This acquisition will help them expand their current operations and provide a strategic partner for Aecon on future joint venture opportunities in eastern Ontario."
Terms of the deal were not released.