[4] Jeptoo showed marked improvement at the Turin Marathon in November, at which she outran Fate Tola to win the race in a new best time of 2:27:02 hours.

[7] Jeptoo had a significant breakthrough at the 2011 Paris Marathon: although she did not expect to win, she successfully held off challenges from Agnes Kiprop and Koren Yal to be the first woman across the line, recording a time of 2:22:55 hours.

[8] She won the silver medal in the 2011 World Championships in Athletics in Daegu, finishing in 2:29:00 and placing second behind countrywoman Edna Kiplagat.

[10][11] She ran a new course record at the New Year's Eve Saint Silvester Road Race, beating Wude Ayalew to win the event.

[20] Jeptoo met Abel Kirui at a training camp and he invited her to visit the Seventh-day Adventist Church that he was a member of.

[21] Jeptoo along with fellow Seventh-day Adventists Abel Kirui and Amos Tirop Matui founded Better Living Marathon.