Former Roma captain De Rossi came in as interim boss when Jose Mourinho was sacked in January and has revitalised the team.
"After meeting yesterday afternoon with Daniele De Rossi, we are delighted to announce he will continue as head coach of AS Roma after this season and for the foreseeable future," said Roma's American owners Dan and Ryan Friedkin.
"We will continue to work together as hard as we possibly can to deliver a future that AS Roma's fans deserve. "We couldn't be happier to build a long-term project with Daniele." Roma are currently fifth in Serie A and in a good position to reach the Champions League for the first time since 2018.
Roma have only lost twice since De Rossi took charge, against Italian champions-elect Inter Milan and Brighton when their last-16 Europa League tie had already been put to bed in the first leg.