The former X Factor contestant confirmed the news in a statement posted on her Tumblr blog. Vickers signed to the label in early 2009 after coming fourth in Simon Cowell's ITV1 competition.
Vickers wrote: "I just want to let you know what the crack is at the moment down in the Vickers camp. Myself and RCA have decided to part company, purely based on a creative level. I will always be really thankful for the time we've spent together and the support they've given me.
"But, I've grown up a lot since the first album and whilst the past couple years have been a lot of fun and a great success, I'm now ready to take a wander down a different, very exciting path! In order to grow, this change has to be made."
Vickers is currently working on the follow-up to her chart-topping debut album Songs From The Tainted Cherry Tree.
"I'm so proud of where the second album is right now and I'm counting down the minutes until it's all ready and you guys can finally hear it," the 19-year-old said of her second collection. "I've been having the best time over the past six months - being creative, working with so many inspirational people, falling in love with LA and growing as an artist."
> Diana Vickers: 'I really believe in my new album'
Meanwhile, a source told The Sun "A deal has been struck between her management and RCA to give Diana back the handful of songs she's already recorded. It puts her in a strong position to negotiate a new deal now."
While Vickers topped the UK singles chart with debut single 'Once', follow-ups 'The Boy Who Murdered Love' and 'My Wicked Heart' charted at number 36 and 16 respectively.
It was previously revealed that Alexandra Burke - who competed alongside Vickers on the 2008 series of The X Factor - had joined RCA after leaving Cowell's Syco label.
Watch Diana Vickers's video for 'The Boy Who Murdered Love' below: