TPI will manufacture the 61.7-metre blades from its new factory currently being built in Izmir, western Turkey.
The 30,000 square metre facility is due to open in 2016. It will become TPI's second factory in Turkey.
The blades will be used on Vestas' V126 turbine (3.3MW or 3.45MW) installed in the Europe, Middle East and Africa (EMEA) region.
The two companies previous signed a supply agreement in 2014, which sees TPI supply blades for Vestas' V110 2MW turbine for use in China.