Barbara McCreery resigned Wednesday as head of Bok High School.
The former principal of Communications Technology High is accused of having erased and changed students' answers on the standardized state PSSA tests in order to spike their scores.
Officials say, for example, 11th grade math test results spiked from 30-percent passing to 70-percent, in the span of a year.
Lola Marie O'Rourke is accused of similar allegations when she was principal of Locke Elementary.
State education officials say they chose to give up their certification instead of getting disciplined.
The city is still investigating 10 schools suspected of cheating, while the state is looking into more than 10 others.