Fishburn Hedges and Band & Brown have been taken on as part of a wider initiative by the department headed by secretary of state Ed Balls. Fishburn Hedges will handle the science and maths subjects, while Band & Brown will promote foreign languages.
Both appointments follow a series of competitive pitches managed by the Central Office of Information.
Fishburn Hedges director Martin Brown said there had been a 'steady decline' in interest in maths and science.
During the three-year campaign, the agency will target 13- to 17-year-olds to show the attractive career opportunities that can result from studying the subjects, such as lighting experts at music festivals and Formula One engineers.
Fishburn Hedges will also target parents and teachers in the campaign, which launches next month.
Brown said: 'We're going to try to open up teenagers to the possibilities that can come their way if they take science and maths.'
Meanwhile, Band & Brown's brief is to increase the number of young people studying modern foreign languages after the age of 14 at GCSE and equivalent level. The 15-month campaign will launch this summer.
Band & Brown group account director Susie Barrett said: 'Making something cool is quite tricky and that's what we need to do. You've got to do it subtly.'
Earlier this week, the DSCF provoked controversy by announcing that oral tests are to be scrapped from foreign language GCSEs because a review of language teaching found them 'too stressful and too short'.