As a math major, would taking an honors math class be beneficial if I am currently planning on applying for grad school?
Do you mean honors math courses in college and graduate study in math?
Yes, assuming that they offer more practice in proofs and hard problems, and you are ready for them. Graduate study in math involves proving conjectures and solutions to hard problems.
Do you mean in HS or in college?
If college, I would ask a college professor about this.
If HS, then yes you should be taking honors/AP classes.
My bad. Yes, i mean college honors classes.
Would they help in admissions for grad school?