Mona first appeared in 'The One After "I Do"'. Mona and Ross began their relationship just as Ross learned that Rachel was pregnant with his child. However, when Ross asked Rachel to move in with him because of the baby, Mona broke up with him.
Her relationship with Ross was often plagued with unfortunate coincidences, such as Ross giving her a key to his apartment before being forced to change the locks and her finding out on Valentine's Day that Rachel had moved in with him.
Mona's relationship with Ross could be described as more friendly than romantic even when they were dating. Ross takes things a lot more slowly with Mona than he did with other girls. A few instances of this was when he was willing to adopt a cat with Julie, and proposed to Emily after dating for only six weeks. In contrast, Ross had met Mona in May during Monica and Chandler's wedding and in "The One With Ross' Step Forward", which takes place in December, he was trying to dissuade her from sending out holiday cards. Their relationship later became complicated due to Ross being the father of Rachel's baby and Ross regularly forgetting dates with her when Rachel had pregnancy problems. Their relationship ultimately ended on Valentine's Day in "The One With The Birthing Video". Two episodes later, Ross sneaks over to Mona's apartment to retrieve his favorite salmon shirt when she returns with another boyfriend. During the credits, Mona comes over to his apartment because she thinks he still has feelings for her (but that wasn't it; he only wanted his shirt back). She admits she still has feelings for him, but it is too complicated for them to work. She asks if she can keep the shirt to remember him by but Ross says no.
Mona also seemed to have a good relationship with Rachel. She was very supportive of Ross and Rachel having a baby (she even bought a t-shirt that says "Fossils are my friends"), but wasn't happy that Ross was forgetting about her when Rachel was having baby trouble, although they still maintained a good friendship. It could be possible that Rachel secretly disliked Mona because Ross had abandoned her for Mona during pregnancy, and Rachel was wanting to talk to him about the possible re-kindling of a relationship. But this seems pretty unlikely- even in Season 2, Rachel despised Ross' girlfriend Julie because she was in love with Ross at the same time. Mona didn't even attend Rachel's baby shower, but that was because her appearances in the show were finished.
Mona and Monica were colleagues at Allesandro's. Although they do not interact much onscreen, it is implied that they have a good relationship since Mona was invited to Monica and Chandler's wedding as well as their Halloween party. It is unknown if they ever saw each other again after Monica left Allessandro's intending to live with Chandler in Oklahoma.
Chandler Bing, Phoebe Buffay, and Joey Tribbiani
Mona also seemed to have a good relationship with Chandler, Phoebe, and Joey. Joey tried to hook up with her the night of Chandler and Monica's wedding, but Ross deterred him by pointing out his small feet.
Mona showed particular dislike for Rachel's father Dr. Leonard Greene after the harsh doctor charged into Ross' apartment and started shouting at him about getting Rachel pregnant and not marrying her afterwards. She was very offended after Dr. Greene called her a tramp and was hoping that her relationship with Ross would not end while Ross and Dr. Greene were bickering about Rachel. (Ross couldn't tell Leonard the truth because he knew it would upset Mona.) Because of that, Mona and Dr. Greene hated each other the same way Ross and Dr. Greene do.
Mona had a new unnamed boyfriend sometime after she and Ross broke up and the relationship was obviously a good one when they are seen passionately making out on the couch. Mona even gave him Ross' salmon shirt to wear after she accidentally spilled wine on his other shirt. The relationship goes on well but it's unknown how long it would continue.
- "The One After 'I Do'" (First appearance)
- "The One With Rachel's Date"
- "The One With The Halloween Party"
- "The One With The Stripper"
- "The One With Ross' Step Forward"
- "The One With The Secret Closet" (Mentioned only)
- "The One With The Birthing Video"
- "The One With The Tea Leaves"
- "The One In Massapequa" (Mentioned only)
- She is Ross' fifth serious girlfriend, which is evident by the fact that he gave her a key to his apartment, although she technically manipulated him into a conversation about how serious they were as a couple. Ross ends up giving her the key to get out of the awkward conversation. Ross' other serious girlfriends up to that point were Carol, Julie, Rachel, and Emily.
- Mona's job at Allesandro's was never specified. Since she spent enough time with Monica to score a wedding invite, she was probably a chef as well.