During his junior season alone, Edmunds accumulated 123 tackles, four sacks, two interceptions, two blocked kicks, and two forced fumbles, and was nominated for Virginia's defensive player of the year.

On January 10, 2018, Edmunds released a statement through Twitter announcing his decision to forgo his remaining eligibility and enter the 2018 NFL draft.

[9] On March 14, 2018, Edmunds participated at Virginia Tech's pro day, but opted to stand on his combine numbers and only performed positional drills.

[22][23] He entered training camp slated as the starting middle linebacker after Preston Brown departed in free agency.

[29] He notched his first sack of the season in week 10 against the Cleveland Browns, taking down quarterback Baker Mayfield in the endzone for a Bills safety.

[30] In week 11 against the Miami Dolphins, Edmunds recorded a team high 12 tackles and made a half sack on Ryan Fitzpatrick in the 37–20 win.

[31] In week 14 against the Baltimore Ravens, Edmunds recorded 8 tackles and his first interception of the season off a pass thrown by Lamar Jackson during the 24–17 loss.

[32] In the AFC wild card game against the Houston Texans, Edmunds recorded a team high 12 tackles, sacked quarterback Deshaun Watson once, and recovered a fumble forced by Tre'Davious White on DeAndre Hopkins during the 22–19 overtime loss.

[35] In Week 9 against the Seattle Seahawks, Edmunds recorded a team high 11 tackles and sacked Russell Wilson once during the 44–34 win.

[36] Despite dealing with a lingering shoulder injury suffered during week 1 against the Jets,[37] Edmunds was able to garner his second Pro-Bowl selection with his play after recovering.

[43] During the Week 15 loss to the Cleveland Browns, Edmunds recorded an interception off of Joe Flacco and returned it 45 yards for his first NFL touchdown.