The hosts, who hadn't scored in their last four games, looked to get the ball rolling early. Chris Brunt had an excellent chance to open the scoring in the 18th minute, but his powerful header at the far-post was superbly pounded away by Kasper Schmeichel to keep the score level.
The visitors found chances increasingly hard to come by. West Brom's towering defence completely dominated in the air and constantly managed to get in front of any half-chance Leicester could muster.
The Foxes grabbed the lead out of nowhere, after a dreadful back-pass from Salomon Rondon was intercepted by Shinji Okazaki and slid into the feet of Jamie Vardy to smash home first time to make it 1-0 to the visitors on the nick of halftime.
Leicester looked to start the second half the same way they ended the first after Vardy played an excellent ball in towards an outstretched Okazaki, who was inches away from doubling the scoring.
West Brom's chances of equalizing came primarily from set pieces, with Michael Dawson coming close in the 56th minute, only for his goal-bound header to deflect off one of his own teammates.
While the hosts piled forward, the Foxes had a couple chances to catch them on the break, with Riyad Mahrez nearly catching Ben Foster out at his near-post with a clever low effort that sailed into the side netting.
The hosts continued to whip crosses into the area as time dwindled down, but their pressure did little to trouble Schmeichel and Leicester saw out the 1-0 victory.
The win leaves Leicester in 11th place and all-but guarantees top-flight safety. With Vardy in excellent form and the defence looking fairly resolute, the Foxes have a good chance to sneak into the top half of the table and end the season on a high note.