"Despite society having invested so much in education, one in four lack a high school diploma when they turn twenty," write Green Party spokespeople Åsa Romson and Gustav Fridolin in an opinion piece for daily newspaper Dagens Nyheter on Sunday.
According to Romson and Fridolin, this means that 13,000 people every year are "never given an honest chance to gain employment and independence."
It also results in societal costs of up to six billion annually, according to the party's calculations.
Much of this sum goes to income support, but also to cover health care costs and benefits, as well as potential rehabilitation costs.
Because of this, the Green Party wants to facilitate a return to school for those lacking a complete high school diploma, by increasing the number of seats in municipal adult education programmes (Komvux) by 2,000 and adding an extra 3,000 spots in the country's colleges.
In a bid to reduce the drop-out rate from Swedish high schools, they suggest individual study plans should be prevalent.
The Green Party also suggest that unemployed youth lacking a high school diploma receive one year's financial aid, without demand for repayment, if they return to finish their education.
"The support should be directed to those with the greatest need, and serve as an extra push over that threshold," write Romson and Fridolin.