The 200-cover site will open in the city's Bluecote House once major works to the surrounding area are completed in 2016.
The husband and wife run brand is in negotiations to acquire eight further sites - five in the Home Counties, and one in Essex, East Anglia and the Midlands following successful openings in Bristol and Salisbury this year.
Since launching in Hove in 2009, Giggling Squid has acquired a £4m loan from Barclay’s Bank to fund their ambition of becoming the UK’s first major Thai chain.
“Ultimately we’re a food-led business and are still having great fun,” said co-founder Pranee Laurillard.
“We are immensely proud that our customers compliment us for still having the welcoming feel of a one-off independent, which is why people think of us as a family of restaurants rather than a chain.”
Giggling Squid currently operates sites in Brighton, Hove, Crawley, Tunbridge Wells, Henley-on-Thames, Reigate, Stratford-upon-Avon, Marlow, Horsham, Sevenoaks, Salisbury and Bristol.