Lalova’s parents, Miroslav Lalov and Lilia Lalova, were athletes. Miroslav was the Bulgarian 200 metres champion in 1966. Lalova began competing in swimming and gymnastics at age 10, and soon switched to track and field. She became the Bulgarian Youth champion in the 100 metres competition in 2000, and placed fourth in the 200 metres at the 2001 IAAF World Youth Championships. At the 2003 European Athletics Junior Championships, she won both the 100 metres and 200 metres events.

On 19 June 2004 in Plovdiv, Lalova tied with Irina Privalova as the sixth fastest woman in 100 metres history (at that time), recording a time of 10.77 seconds. At the 2004 Summer Olympics, she placed 4th overall in the women’s 100m competition, and 5th in the 200m. At the 2005 European Athletics Indoor Championships, she was awarded a gold medal for her time of 22.91 seconds in the 200m.

On 14 June 2005, Lalova’s career was interrupted when she broke her right femur after a collision with another athlete while warming up the 100 mt sprint at the Athens Super Grand Prix. In June 2006 the Bulgarian Olympic Committee awarded her the IOC ” Sports ad FairPlay” prize for her conduct in the aftermath of the incident, when she declined to seek compensation from her fellow competitor or the event’s organizers.

Lalova was appointed to the European Athletic Association Athletes Commission for 2006-2010 and from 2014-2018 following an election held in August at the 2006 and 2014 European Athletics Championships.

Lalova returned to competitive racing on 29 May 2007, at the Artur Takač Memorial in Belgrade, winning the 100m in a time of 11.26 seconds. In August 2007 she reached the quarterfinals of the women’s 100m sprint at the IAAF World Championship in Osaka but failed to progress, finishing in fifth place with a time of 11.33 seconds.

At the 2008 Summer Olympics, Lalova was eliminated in the semifinals of the Women’s 100m, finishing her heat in seventh place with a time of 11.51 seconds, and was eliminated in the second round of the Women’s 200m.

In March 2011 she moved to Italy, joining the group of Professor Roberto Bonomi. Later in 2011 she started her season with 11.08 and 22.66 and after a week won the 100m Diamond League event in Oslo with 11.01. After another week she ran the second best time of her career – 10.96 during the Balkan Championships in Sliven, Bulgaria.

Later in the season, she reached her first World Championships Final in the 100 metres in Daegu finishing 7th.

During the World Indoor Championships 2012 in Istanbul she managed to rich the final of 60 metres finishing 8th.

At the 2012 European Athletics Championships in Helsinki, Lalova ran the distance in 11.06 during Round 1, setting the leading European result of the year so far. She went on to win her heat in the semifinals, as well as the final on 28 June, beating Olesya Povh and Lina Grinčikaitė for her second career gold medal from a major championship.

At the 2012 Summer Olympics in London, Lalova finished second in her heat during the quarterfinals on Women’s 100 Metres, equaling her season best of 11.06. She was eliminated in the semifinals, where she ran the distance for 11.31, finishing 6th in her heat and 19th overall. At the 200 metres distance she finished 5th in her heat with a season-best time of 22.91. In the semifinals she ran the distance for 22.98, finishing 6th in her heat and missing on a place in the final.

In December 2012 Lalova opened her own sports club under the name Ivet Lalova Sprint Academy, meant to help amateur, children, youth and professional athletes in Bulgaria.

In 2013 European indoor Athletics Championships in Goteborg she won a bronze medal with a personal best time of 7.12.

In her first 2013 IAAF Diamond League appearance, Lalova finished third in the 200m sprint at the Golden Gala in Rome, with a personal season-best time of 22.78 (+1.2 m/s). This was also the best time for a European athlete so far throughout the year. She continued well in the next round at the Bislett Games in Oslo, winning the 100m sprint with a season best of 11.04. She then finished 3rd in the 200m at the British Grand Prix on 30 June, with a time of 23.02.

In Moscow, at the World Championships she got to 9th place in both sprint events 100-200 metres setting the time of 11.10 and 22.81.

At the 2014 European Athletics Championships, she finished 5th in the Women’s 100 m with a time of 11:33.

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.

At the 2016 European Athletics Championships in Amsterdam Lalova recorded a season best time of 22.57 in the Women’s 200 metres semifinal, tied with Dina Asher-Smith for the fastest qualifying time in the discipline. In the final she improved her time to 22.52 and won Silver, her second major medal from European Championships and the first 200 m Euro medal ever for Bulgaria. In the Women’s 100 metres Lalova won her heat in the semifinals with a time of 11.26, before clinching her second Silver of the tournament with 11.20 in the final.

In the first 200 m event of the 2016 IAAF Diamond League, the Shanghai Golden Grand Prix, Lalova reached the final, placing 4th with a time of 23.04.^[ On 18 May she won the silver medal in the 100 m event at the 2016 Beijing IAAF World Challenge, with a season best time of 11.11. Lalova then participated in her second Diamond League event of the year, the 2016 Golden Gala in Rome, finishing 4th in the 100 m final with a time of 11.15. On 6 June she won the Women’s 100 m at the 2016 Gala Dei Castelli in Bellinzona, Switzerland, setting a time of 11.19 in the semi-final, and 11.20 in the final itself. Lalova’s third Diamond League event of the year was at the 2016 Bislett Games in Oslo, Norway, where she won the bronze medal in the 200 m event with a season’s best time of 22.78.

At the Rio 2016 Olympic Games, where she was the Bulgarian Flag bearer, Ivet reached the semifinal of the 100 m with the time of 11.31 and after 2 days she win her heat of the 200 m, finished second in the semifinal with the season best of 22.42 and qualified for the final where she arrived 8th with the time of 22.62.

Lalova opened her 2017 season by winning both the Women’s 100 and 200 metres events at the Golden Grand Prix in Kawasaki, the third round of that year’s IAAF World Challenge. She first triumphed in the 200 metres final with a time of 22.98, before winning gold in the 100 metres competition later that day with a time of 11.40. At the 2017 World Championships in London she ran her season best time in the semifinals of 100 metres in 11.25  and she reached 9th place in the 200 metres with the time of 22.96.