Liverpool's Mason Media has won the business, having held Ethel's corporate account since October 2005.
The agency will handle comms around the retailer's aggressive expansion drive under recently appointed CEO Simon Cooper.
Mason Media director Nick Mason said it would primarily target publications that have a focus on value.
Mason added that Ethel, founded 72 years ago, 'pioneered value clothing long before any rivals'.
The retailer, which has 310 stores, was acquired by ABN AMRO Capital for £122m in June 2004.