Tsimikas joined Liverpool from Olympiacos on a five-year contract in 2020 and the terms of the 27-year-old's new deal have not been disclosed.
The Greece left-back told Liverpool's official website: "I feel very glad to be here to extend my contract. I feel like all the sacrifices I did and other things, the work I put in, everything pays off.
"But this keeps me fully motivated for the rest. As I've said in many, many interviews, this team has many, many things to achieve all together and I wanted to be from the first minute a part of it."
Tsimikas has made 63 appearances and provided 12 assists since joining Liverpool for a fee of around £11.7million.
He has made one Premier League appearance this season, off the bench against Bournemouth in August, and started in last week's Europa League win against LASK in Austria.