How many years of school are require for forensic psychology?

If you wish to have your PhD in Forensic Psychology then it should take you approximately 7 years. 4 years should be required for your undergraduate degree, 1 year to complete your Master's Degree and 2 years to finish your Doctorate Degree. This can vary, depending on the student. You can also probably be an assistant in the field by getting your undergraduate degree in 4 years, but the pay would be significantly lower and so would your level of expertise.