The former Miss Great Britain, 30, hit back after reading Reveal's article about Emma's comments in the latest Love Island episode.
Emma had said: "She's just a nasty bitch. She is spiteful. A selfish bitch."
Firing back, Sophie tweeted: "So coming in to ruin your ex's relship isn't selfish? & slagging me off while wearing my dresses... classic mean girl! (sic)"
She was backed up by ex-islander Malin Andersson, who tweeted: "Emma is vile.. We can all see it. They both suit."
Malin's then-boyfriend Terry Walsh ditched her for Emma after Malin was eliminated.
Emma made her comments to Kady McDermott after Sophie cooled things down with Katie Salmon in order to preserve her relationship with Tom Powell.
Trainee project manager Emma had suggested Sophie was playing a game when she coupled with Katie, which Kady agreed with.
"She thought she would fly in on Katie's wings," said Emma, adding: "I'm sorry, you don't love someone one day, then not the next, then love them again the next day, then not the next.
"I thought I understood Sophie when I first came in and we were very similar. But we could not be more worlds apart."
Emma came in as Tom's ex-girfriend and everyone predicted she and Sophie would NOT get on. But that couldn't be further from the truth as they quickly formed a friendship.
But that amicability came to an end during a massive row. Sophie disagreed with Emma's decision to have sex with Terry Walsh when she'd vowed not to sleep with anyone on TV, and Emma was furious when she heard Sophie claim she had a game plan.
Sophie told Reveal after her exit: "I think she's playing a game in the sense that she came in to try and f*** things up for Tom. I don't know if she's playing the Love Island game to win it.
"From what I've seen and heard now that I've come out - which is that she was obviously in there to get a reaction out of Tom and maybe make him jealous - I think she just came in to cause trouble."
Love Island airs nightly at 9pm on ITV2.