You Aren't the Boss of Me (Or Are You?)

Dear Experts, I have been in my new job for 3 months. I have a co-worker who does exactly the same thing as me (we are both account managers) but for a different group of customers. She's been in her job 1 year. However, it appears as though she thinks she is in charge of me. We report to the same boss and have the same title, but whenever things come up that need to be done by one of us, she picks the jobs she wants to do and then delegates the rest to me. Not once has there been a discussion as to who should do what - I never get a say. Instead, she just announces it and tells me what to do. I was good about this when I started the job, but now I'd like to stop it before it gets out of hand. What should I do? I am starting to really resent her for it and I don't want to end up hating my co-worker. Here is how our T.A.P. experts answered this question: Q#235 When get work fr boss, say "this time, I'll do x instead of y" as u know ropes & need other experience. ( @juliaerickson ) Q#235 I'd reply via email to boss & coworker next assignment w/my preferences. I'd reply FAST & do VERY well. ( @beneubanks ) Q#235 (STEP 1) Ask for meeting w/boss & seek advice on the best way to approach your co-worker. ( @jtodonnell ) Q#235 (STEP 2) You'll score points w/boss for trying to solve it on own & make him aware of situation too. ( @jtodonnell ) Q#235 Invite her for coffee and discuss your concerns one-on-one. Sometimes a change of setting can help change attitudes. ( @gradversity ) Q#235 Politely challenge her. You teach people how to treat you & you've taught her it's OK to boss you around. ( @dawnbugni ) Q#235 It will take time to re-train her, but worth it. "If UR tired of being treated like a doormat, stand up." ( @dawnbugni ) Our Twitter Advice Project (T.A.P.) is no longer an active campaign. To find an answer to the above question, please use the "Search" box in the right-hand column of this website.