The deal covers the design of blade rack, tower and nacelle fastenings to be used during the transport of Siemens 6MW turbines to the project site.
Siemens said that it is the first such contract won by a UK firm.
Galloper project Project Procurement Manager Christoph Schott said, "Siemens is delighted to be able to award Houlder Ltd this important contract.
"It further underlines our commitment, as demonstrated by the construction of our blade manufacturing factory in Hull, to UK content and to keeping our operations and supply chain as close to the customer as we are able.
"Previously, all such design work had been sourced from Denmark or the Netherlands. We look forward to a long and productive association with Houlder."
The Galloper wind farm will have 56 of 6MW Siemens SWT 6.0-154 turbines that produce enough energy about 336,000 UK households. The wind farm is located 27km off the coast of Suffolk.
Gallopwer wind farm was approved in the year 2013 and construction began in November 2015. The total cost of the project is estimated to be £1.5 bn.
It is the extension of an existing and fully operational Greater Gabbard offshore wind farm off the coast of Suffolk.
