The 30-year-old player will join the team at the Hawthorns, the club's home stadium, for the remainder of the season.
Andrew Nestor, West Brom's sporting director, expressed his enthusiasm for the new signing, stating that Collyer's skills and abilities will complement the team's existing midfield players.
"Toby is a dynamic player with excellent physical attributes, who can contribute to our team's success with his progressive play and passing ability," Nestor said.
Collyer may make his debut on Saturday when West Brom travels to Wrexham for a match.
