| Election Name: | 2011 Seoul mayoral by-election |
| Country: | Seoul |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 2010 Seoul mayoral election |
| Previous Year: | 2010 |
| Election Date: | 26 October 2011 |
| Next Election: | 2014 Seoul mayoral election |
| Next Year: | 2014 |
| Turnout: | 4,066,566 (48.56%) |
| Candidate1: | Park Won-soon |
| Party1: | Independent politician |
| Popular Vote1: | 2,158,476 |
| Percentage1: | 53.40% |
| Candidate2: | Na Kyung-won |
| Party2: | Grand National Party |
| Popular Vote2: | 1,867,880 |
| Percentage2: | 46.21% |
| Mayor | |
| Before Election: | Oh Se-hoon |
| Before Party: | Grand National Party |
| After Election: | Park Won-soon |
| After Party: | Independent politician |
The 2011 Seoul mayoral by-election was held on 26 October 2011 after Oh Se-hoon resigned due to his failure in the Seoul Free Lunch Referendum. It was part of the by-elections in 2011.
As the controversy over the free school lunch program has not subsided, Mayor of Seoul Oh Se-hoon proposed a local referendum to the Seoul Metropolitan Council to directly ask the citizens' opinions regarding the free school lunch program.[1] But the Metropolitan Council rejected his proposal, finally under the leadership of Mayor Oh, it decided to hold a local referendum on the scope of free school lunch, and the vote was scheduled to take place on 24 August 2011.
On 21 August, Mayor Oh announced three days before the referendum that he would step down if he lost because of unachievable voter turnout not achieved or low approval ratings after counting.
In the referendum held on 24 August, it was not able to count the votes because it was less than the minimum turnout rate of 33.3%. This has raised interest in the timing of Oh's resignation, because the by-election date will vary depending on his resignation date.[2] If he resigns after 30 September 2011, the mayoral by-election will take with the legislative election on 11 April 2012. So the Grand National Party called for him to resign in October 2011. However, Mayor Oh announced his resignation on 26 August.[3]
Na Kyung-won was the only candidate in the Grand National Party to run alone. Other candidates initially ran, but withdrew.
The candidate who received the highest support in pan-opposition was Ahn Cheol-soo. However, he was on 6 September 2011, expressed its endorsement of Park Won-soon, a lawyer.[4] [5]
On 3 October 2011, pan-opposition primary were held to claimed unification of opposition candidates. In this primary, Park Won-soon was elected as the single candidate for the pan-opposition bloc by defeating Park Young-sun of the Democratic Party and Choi Kyu-youp of the Democratic Labor Party.[6]
| Districts | Na Kyung-won | Bae Il-do | Park Won-soon | Total votes | ||||
|---|---|---|---|---|---|---|---|---|
| Votes | % | Votes | % | Votes | % | |||
| Jongno District | 31,926 | 45.63 | 277 | 0.40 | 37,770 | 53.98 | 69,973 | |
| Jung District | 26,564 | 47.66 | 210 | 0.38 | 28,965 | 51.97 | 55,739 | |
| Yongsan District | 50,847 | 51.83 | 338 | 0.35 | 46,923 | 47.83 | 98,108 | |
| Seongdong District | 54,059 | 45.33 | 435 | 0.37 | 64,766 | 54.31 | 119,260 | |
| Gwangjin District | 63,128 | 43.81 | 514 | 0.36 | 80,449 | 55.83 | 144,091 | |
| Dongdaemun District | 65,140 | 45.24 | 614 | 0.43 | 78,221 | 54.33 | 143,975 | |
| Jungnang District | 68,501 | 44.76 | 676 | 0.44 | 83,870 | 54.80 | 153,047 | |
| Seongbuk District | 81,902 | 42.74 | 743 | 0.39 | 108,976 | 56.87 | 191,621 | |
| Gangbuk District | 54,531 | 42.57 | 555 | 0.43 | 72,981 | 56.97 | 128,097 | |
| Dobong District | 64,110 | 44.88 | 567 | 0.40 | 78,179 | 54.73 | 142,856 | |
| Nowon District | 104,251 | 44.08 | 955 | 0.40 | 131,293 | 55.52 | 236,499 | |
| Eunpyeong District | 78,252 | 42.65 | 712 | 0.39 | 104,533 | 56.97 | 183,497 | |
| Seodaemun District | 55,181 | 43.04 | 495 | 0.39 | 72,542 | 56.58 | 128,218 | |
| Mapo District | 67,297 | 42.01 | 511 | 0.32 | 92,375 | 57.67 | 160,183 | |
| Yangcheon District | 89,227 | 45.98 | 1,052 | 0.54 | 103,780 | 53.48 | 194,059 | |
| Gangseo District | 95,934 | 44.14 | 874 | 0.40 | 120,537 | 55.46 | 217,345 | |
| Guro District | 71,850 | 43.15 | 646 | 0.39 | 94,015 | 56.46 | 166,511 | |
| Geumcheon District | 36,194 | 41.12 | 402 | 0.46 | 51,418 | 58.42 | 88,014 | |
| Yeongdeungpo District | 73,833 | 46.01 | 567 | 0.35 | 86,069 | 53.64 | 160,469 | |
| Dongjak District | 73,341 | 43.60 | 583 | 0.35 | 94,283 | 56.05 | 168,207 | |
| Gwanak District | 78,473 | 36.86 | 857 | 0.40 | 133,587 | 62.74 | 212,917 | |
| Seocho District | 111,014 | 60.12 | 488 | 0.26 | 73,139 | 39.61 | 184,641 | |
| Gangnam District | 140,109 | 61.33 | 672 | 0.29 | 87,657 | 38.37 | 228,438 | |
| Songpa District | 140,183 | 51.12 | 947 | 0.35 | 133,087 | 48.53 | 274,217 | |
| Gangdong District | 92,033 | 47.98 | 718 | 0.37 | 99,061 | 51.65 | 191,812 | |
| Total | 1,867,880 | 46.21 | 15,408 | 0.38 | 2,158,476 | 53.41 | 4,041,764 | |