One day at a previous job, my Coworker left their pay stub sitting in a shared space. I didn’t mean to snoop, but in looking to see what they had left I accidentally saw their take-home sum. I immediately wished I could erase this forbidden knowledge, but like Game of Thrones spoilers on the internet I had already seen too much.

Whoever said the grass is greener on the other side must have been talking about salary discrepancies.

I was upset, not because my coworker made so much money, but because I made much less working in the same position for the same amount of time. I immediately started questioning everything about my employment. Was I being taken advantage of? Was I worth less than my coworker? Did I do something wrong to preempt future raises?

I may be the only person dumb enough to read a pay stub, but I’m definitely not the only person who’s found themselves in this position. If you find out that you earn less than your coworkers, here are some things you can do.

Ask for a Raise

If you decide to ask for a raise, your primary reason can’t be that you found out you’re earning less than a coworker. A supervisor will assume you’re just being greedy, and instead of a higher wage you’ll leave the meeting with a higher chance of being passed over for future raises and promotions.

Instead, make a list of how you’ve made money or increased productivity – bonus points if you have specific figures to back up your claims. Then, do some research on what other people in your position at similar companies earn. Make sure to compare people who have the same cost-of-living as you. If you’re based in Mobile, Alabama, don’t measure your salary against someone from the Bay Area, for example.

Schedule a meeting with your boss to ask for a raise. Bring a list of accomplishments and proof of your efforts, such as emails from satisfied clients or spreadsheets with empirical data. Do not mention how much your co-worker is making. Your boss probably already knows, and bringing it up will seem like you’re accusing them of bias.

Find a New Job

If your boss doesn’t agree to a raise and you still feel like you’re not being treated fairly, your only recourse is to find a new job. If you stay, you’re reinforcing to your employer that they don’t have to pay their employees what they really deserve.

If you do an exit interview with a member of the HR department, you can bring up the payroll discrepancies as a reason for your departure. It may not help your situation, but you’ll feel better after airing your grievances – and potentially prevent the same thing from happening to another employee.

Talk to HR

Unfortunately, with pay discrepancies there’s always a chance of genuine discrimination. If you suspect your lower wage is due to your gender or race, schedule a meeting with HR to discuss the problem.

Bring any evidence of past discrimination with you. You may have trouble proving that a hiring manager was motivated by racial or gender-biased leanings when they offered you a low starting wage, but HR departments tend to take accusations of discrimination very seriously. If you feel your concerns aren’t being properly addressed, consider contacting the federal Equal Employment Opportunity Commission, who oversee compliance for most federal anti-discrimination and anti-harassment laws.

Do Nothing

This probably isn’t the answer you’re looking for, but wage discrepancies are a complicated issue. You might not know the full story behind why your co-worker is earning more than you. Instead of bursting into your boss’s office in a rage, take some time to cool off. The first reaction you have might not be the most mature one.

Even if you’re close with your coworkers, don’t assume you know the real reason why they’re earning so much. Maybe they have a special qualification you don’t have or experience in a crucial field. Maybe they took a harder line during contract negotiations. Think of it this way: Does it seem more likely that your employer is discriminating against you, or that some other factors are at play?

Examine your own salary compared to what the industry averages are. Do you earn more or less than others in your field? Do you get special perks other employees don’t, such as tuition reimbursement or five weeks of paid vacation? It’s possible that other employees are looking at you enviously for different reasons.

Zina Kumok is a freelance writer specializing in personal finance. A former reporter, she has covered murder trials, the Final Four and everything in between. She has been featured in Lifehacker, DailyWorth and Time. Read about how she paid off $28,000 worth of student loans in three years at Debt Free After Three.