The Nottingham-based company provides services to customers across six continents in seven languages.
Littlefish will take space at Steel City House and is set to create about 150 jobs in 2020. It will provide managed IT services, cyber security, cloud services and IT consultancy.
Mark Petty, sales and marketing director at Littlefish, said: "We are delighted to announce the opening of our new, strategically important Sheffield Office.
read the rest here