
The appointment follows the company's recent appointment of Srini Gopalan to the role of chief marketing officer.
Wylde replaces Chris Barrow, who left T-Mobile in April to spend time with his family.
Wylde joins T-Mobile from Lloyds TSB General Insurance where she was responsible for customer marketing.
Previously Wylde spent six years at Vodafone, followed by three years at O2 as head of corporate marketing.
Wylde will start at T-Mobile on 22 June.