At the 2015 World Championships in Athletics in Beijing Lalova recorded a season best 11.09 in the 100 metre qualifiers, but failed to pass the semifinal stage. In the 200 metre discipline she recorded a season best time of 22.54, qualifying for the semifinals. There she ran the distance in 22.32, qualifying for the final and setting a new personal best. In the final she finished 7th with a time of 22.41, becoming only the third Bulgarian female athlete to participate in a 200m final at a World Championship, and the first one since the World Finals in Rome in 1987.