Yes, 5.0 is typically the highest possible GPA. In most grading systems, a GPA is calculated based on a 4-point scale, where each letter grade corresponds to a certain number of points. For example, an A may be worth 4 points, a B may be worth 3 points, and so on. A GPA is then calculated by dividing the total number of points earned by the total number of credits attempted. A perfect GPA of 5.0 would indicate that a student has earned all A's in all of their classes.
Some schools may use different grading scales or have different ways of calculating GPAs, but in general, a GPA of 5.0 is considered to be the highest possible.