Five new businesses will be joining Croxley Green Business Park.
The new lettings will be in Millfield House, each totalling between 2,000 and 3,000 square foot, with an average lease length of five years.
The park, which is owned and managed by Threadneedle Investments, also signed over new units to Kodak and Howdens earlier this year.
Discussions are now under way to lease the two remaining 5,300 square foot units in the same building.
Rob Flavelle, asset manager at Threadneedle, said: "With the arrival of the Metropolitan line extension in 2017, Croxley Green will continue to prosper and businesses based on the site will reap the benefits."
The news of these lettings comes after a multi-million pound refurbishment programme to renovate a large number of offices on the 75-acre business park was announced earlier this year.