The Venezuelan made the move to Lotus from Williams in November but is yet to score a point for the team in the current campaign.
He is one of six drivers who are currently without a point, leaving cash-strapped Lotus languishing eighth in the drivers' standings.
However, Lopez confirmed the 2012 Spanish Grand Prix winner will remain next term, adding his confidence that the 29-year-old will prove a useful asset for the team.
"As it's half way through the season I can confirm 50 per cent of our driver line-up for 2015 as Pastor is with us for next year," he told Lotus' official website.
"Despite the difficulties we've had so far this season, he recognises our true potential as a team and we recognise his true potential as a driver. We will achieve great things together.
"Looking forward, we have been able to take steps to ensure that 2014’s lessons have been learnt and we get back to where we want to be in 2015 – fighting for podiums."
Maldonado will start Sunday's German Grand Prix from 19th on the grid with team-mate Romain Grosjean four places ahead.