Handley will lead international communications for cloud-based email management firm Mimecast as group comms director.
He will handle all global comms for the company, including PR, analyst relations and social media.
Mimecast chief strategy officer Matthew Ravden said: 'Stuart brings a combination of big brand communications and entrepreneurial experience.
'He will play a key role as we push on with our international growth plans,' he added.
Global comms manager Ruth Armitage will report to Handley, who said the role was 'hard to turn down' and that he was happy to 'get his teeth into a UK business'.
His initial comms strategy for Mimecast will be to keep PR activity in line with the growth of the business, particularly in the US.
Handley headed comms for Dell across EMEA, Latin America and Canada for four years before departing in May 2012.