Thuney will make $17.5 million per year as part of the new deal, setting him at $51 million over the next three years with $33.5 million guaranteed.
Chicago acquired Thuney in a trade deal with the Kansas City Chiefs earlier in the offseason.
Thuney's 8.5 sacks given up since 2021 is the fewest by any guard, or tackle, in the NFL with over 2,000 passing snaps.
He didn't allow a single sack last season while on the Chiefs, which ranked the best out of 136 eligible guards.
Pro Football Focus gave Thuney a 79.9 overall grade last season (82.0 in pass blocking, 73.5 in run blocking), earning him First-Team All-Pro honours for the second straight season and his fourth All-Pro honours entirely (Second-Team in 2019 and 2022).
The Bears will now look to continue to give young quarterback Caleb Williams the offensive line he so desperately needed last season.