Talented was formed in 2000 and has a fee income of just under £500,000. Clients include the Territorial Army, British Army and the SNP.
GS group CEO Chris Lovell said: 'In order to operate effectively in Scotland we have to be there. Scottish media contacts are crucial, and that is what Talented has.'
The acquisition means GS has ten offices, five of which have been opened in the past 18 months.