Dil Juunglee follows the love story of Sumit Uppal (Saqib Saleem) a gym trainer who aspires to be a film actor and Koroli Nair (Taapsee Pannu) an English teacher. Sumit joins Koroli’s classes to learn to speak good English, and in the interim the two soon grow fond of one another and fall in love. One day, Koroli and her two friends – Shumi (Sristi Shrivastava) and Geetika (Ayesha Kaduskar) – go for a picnic with Sumit and his friend, Prashant (Abhilash Thapliyal). In a freak accident, Koroli falls into a lake but Sumit is unable to save her from drowning because of his fear of water. Even otherwise, Koroli and her two friends realise that Sumit is very self-centred. Despite that, Koroli agrees to marry Sumit but minutes before the marriage is to be solemnised, she understands that Sumit is not happy about marrying her. One of the reasons is that Sumit doesn’t find her suitable enough. However, when Koroli realises that Sumit will not take the drastic step, she herself calls off the marriage. The two part ways.
After the called off marriage Koroli returns to England and joins her father’s business, followed by her marriage being fixed with Jai Singh Rathod (Santosh Barmola), a rich young man. In the meantime back in India, Sumit becomes an actor but manages to get work in inconsequential films. However, one such film takes him to England where Sumit, quite by chance, meets Koroli and realises that she is a new and super-confident girl now, and sparks fly between Sumit and Koroli.
What happens thereafter? Does Koroli marry Sumit or Jai? Are some of the questions that make up the rest of the film.