What is the IQ requirement for a Ph.D?

There's no IQ requirement for a Ph.D. Universities don't require or test for IQ scores as part of the admissions process. Admission is based on factors like GPA, GRE scores (in some programs), letters of recommendation, research experience, and a statement of purpose demonstrating research interest and aptitude. While high intelligence is certainly beneficial for success in doctoral studies, it's not a quantifiable barrier to entry.