Sonia O'Sullivan (born 28 November 1969) is an Irish former track and field athlete. She won a gold medal in the 5000 metres at the 1995 World Championships and a silver medal in the 5000 metres at the 2000 Olympic Games. Her 2000 m world record of 5:25.36, set in 1994, stood until 2017.
O'Sullivan first came to prominence when winning the 1500 m at the 1991 Universiade, before going on to finish fourth in the 3000 m final at the 1992 Olympic Games. She then won a silver medal in the 1500 m at the 1993 World Championships. She was favourite for the 5000 m title at the 1996 Olympic Games but dropped out of the final due to illness. As well as her 1995 World title, she won three gold medals at the European Championships, in the 3000 m (1994), 5000 m (1998) and 10,000 m (1998), and is a two-time World Cross Country Champion.
O'Sullivan won silver medals in the 5000 m and 10,000 m at the 2002 European Championships and competed at her fourth Olympic Games in 2004. She is known for her fast kick, clocking 28-second final 200 m splits in some of her races.
She is one of two women who won the short and long course World Cross Country title at the same championship (1998 in Marrakesh).
Born in Cobh, County Cork, O'Sullivan was educated at St Marys National School Cobh and Cobh Community College. She completed her leaving certificate in 1987. O'Sullivan's first major international competition was the 1990 European Championships at Split, where she finished 11th in the 3000 m. However, O'Sullivan improved quickly after that, and on 26 January the following year, at Boston, she set a new world indoor record in the 5000 m of 15:17.28, taking more than 5 seconds off the old record. At the time, O'Sullivan (who attained a sporting scholarship) was studying accountancy at Villanova University in the US, and at the World Student Games at Sheffield in July 1991, she won the 1500 m gold medal in 4:12.14, and the silver medal in the 3000 m in 8:56.55. At the start of 1992, she finished 7th in the World Cross Country Championships.
She won the Honda Sports Award as the nation's top female cross-country runner in 1991–92.
In 1992, O'Sullivan improved her personal bests in a number of distances between 800 m and 5000 m, setting six Irish national records in the process, including five in the space of 11 days in mid-August following the Barcelona Olympic Games. At Barcelona, in the 3000 m final, O'Sullivan was always in contention and hit the lead in the back straight on the final lap, but she was eventually outsprinted and finished fourth. Narrowly missing out on an Olympic medal was made all the more frustrating when the silver medalist from the race Tatyana Dorovskikh tested positive for a banned substance the following year. In the 1500 m, she finished only 11th in her semi-final and did not qualify for the final. She finished 1992 by winning the Grand Prix Final for the 5000 m.
In 1993, O'Sullivan established herself as one of the world's top middle-distance runners. By the time the World Championships came around, she was the clear favourite for both the 3000 m and 1500 m. However her hopes in the 3000 m were dashed by the performances of three Chinese athletes who would later in the year go on to smash the world record multiple times. The winner, Qu Yunxia, finished in a championship record of 8:28.71, with Zhang Linli and Zhang Lirong following in second and third respectively. A month later Qu would go on to set a 1500 m world record of 3:50.46. O'Sullivan finished the race 4th in a time of 8:33.8. Six days later she won the silver medal in the 1500 m in a time of 4:03.48, again behind a Chinese athlete. Five days after the championships, at the ISTAF meet in Berlin, O'Sullivan recorded the season's best time over 5000 m of 14:45.92, which moved her to third on the all-time world list. Soon afterwards she closed the year by winning the Grand Prix Final for the 3000 m and finished 2nd in the Mile. She finished the Grand Prix season in 2nd place in the Women's Overall competition.
During 1994, O'Sullivan dominated international distance running. She set the fastest time of the year in four events, the 1500 m, 1 mile, 2000 m and 3000 m, and the second fastest time in the 5000 m. On 8 July, at Edinburgh, she broke the 2000 m world record, setting a new time of 5:25.36. This record stood until Genzebe Dibaba of Ethiopia broke it on 7 February 2017. The next week, in London, she broke the European record for the 3000 m, beating Britain's Yvonne Murray, and setting the year's fastest time of 8:21.64. This moved her to fifth on the all-time world list, behind the four Chinese runners who had set their personal bests at the 1993 National Championships in Beijing. This record lasted until 2002, when Gabriela Szabo bettered it. Only three days later, at Nice, O'Sullivan recorded the year's fastest 1500 m, a personal best, of 3:59.10, and only four days after that, she won the mile at the Bislett Games in Oslo, in a time of 4:17.25. This was the season's best, and it moved O'Sullivan to fourth on the all-time world list. All four of these times were also new Irish records, and after this two-week period of record-breaking, O'Sullivan became a clear favourite to win any event she chose to compete in at the European Athletics Championships in Helsinki in August. At Helsinki, O'Sullivan elected to only contest the 3000 m, with her main opposition expected to come from Yvonne Murray. In the final, on 10 August, Murray set the pace with O'Sullivan on her shoulder. With 200 m to go, O'Sullivan surged past Murray to win easily in 8:31.84. O'Sullivan followed this with a win over 5000 m in the Grand Prix final in Paris on 3 September. She finished the Grand Prix season in 3rd place in the Women's Overall standings. At the end of a long season, on 9 September, the tired O'Sullivan finished only fifth in the 1500 m at the World Cup in London.
O'Sullivan continued to dominate international distance running in 1995. As she had done in 1994, O'Sullivan set the fastest time of the year in four events, the 1500 m, 1 mile, 2000 m and 3000 m, and the second fastest time in the 5000 m. O'Sullivan was the winner of 11 of the 12 races in which she competed over 1500 m or 1 mile in 1995. These victories included the only sub-4-minute 1500 m time recorded during the year, a new Irish record of 3:58.85 set at the Herculis meet in Monaco on 25 July. In the 3000 m, O'Sullivan was clearly in a class above her rivals, winning all five of her races, and producing four of the six fastest times, including the year's fastest time of 8:27.57 at the Weltklasse meet in Zürich on 16 August. Her other 3000 m victories included the Bislett Games in Oslo on 21 July, and the Grand Prix final in Monaco on 9 September. O'Sullivan was left with the dilemma leading up to the World Championships at Gothenburg, of whether to compete in the 1500 m or the 5000 m. She had been unbeaten at 5000 m before Gothenburg, although the fastest time of the year, a new world record, had been set by Portugal's Fernanda Ribeiro. In the end, O'Sullivan chose the 5000 m, and, after easily winning her heat on 10 August, she kicked clear of Ribeiro in the final two days later, to win the world title in 14:46.47. Three weeks later, on 1 September, at the ISTAF meeting in Berlin, O'Sullivan again battled over 5000 m with the new world record holder Ribeiro, and again O'Sullivan was victorious, winning in a time of 14:41.40, a new Irish record, and the third fastest 5000 m of all time. For the fourth year in a row, she won the Grand Prix Final, this time over 3000 m.
Although she was not as dominant as she had been in 1994 and 1995, Sonia O'Sullivan continued to be a major force in 1996 at the distances between 1500 m and 5000 m. Her best event in 1996 was the 3000 m, where she was unbeaten for the third successive year, winning all five of her races. O'Sullivan produced the early season leading time of 8:42.40 in Eugene on 26 May, and then at Nice, on 10 July, she recorded the year's fastest time of 8:35.42. In the 1500 m, only two women broke 4 minutes during the year, one of whom was O'Sullivan, who clocked her best time of 3:59.91 when winning at the Bislett Games in Oslo on 5 July. In terms of preparation for the Olympic Games held later that year in Atlanta, O'Sullivan's best event appeared to be the 5000 m, the distance at which she was the reigning world champion. On 5 June, at the Golden Gala meet in Rome, O'Sullivan won in 14:54.75. A month later, on 12 July, at the Securicor Games in London, she beat a strong field to win in 14:48.36. The program at the Olympic Games in Atlanta was sufficiently scheduled to allow O'Sullivan to contest both the 5000 m and 1500 m events. Her early season form and world title the previous year had made her one of the favourites for the 5000 m; however, news of double-world record holder Wang Junxia competing made many observers revise their opinion. In the heats everything seemed on track when she easily won her heat in 15:15.80. However, in the final on 28 July, she was badly affected by a stomach upset, and after starting well gradually faded away and failed to finish. The race was won by 3000 and 10,000 m world record holder Wang Junxia of China. Her disappointment continued in the 1500 m, where, still weakened, she came second last in her heat and failed to qualify for the semi-finals.