Alex and Rosie have been best friends for almost as long as they can remember. On Rosie's 18th birthday party Alex kisses Rosie, who is drunk, and realises that he has romantic feelings for her. However, the day after her 18th birthday, Rosie is upset about having got drunk, and tells Alex that she wishes the night had never happened. Alex interprets this as Rosie just wanting to be friends.
Greg, the "fittest guy in their year", asks Rosie to the school dance. She originally intended to go with Alex but accepts Greg's offer when she learns that Alex is thinking about going with a girl named Bethany. After the dance, Rosie has sex with Greg, but the condom slips off inside her.
Rosie gets accepted to a hotel management course at Boston University. She rushes to tell Alex but finds him having sex with Bethany, which causes her to vomit. She discovers that she is pregnant. She refuses to tell Alex, fearing that he will forego his chance to study at Harvard to help take care of her. After Alex leaves for America she gives birth to a daughter, whom she names Katie. Alex learns of Rosie's pregnancy from Bethany and becomes Katie's godfather.
Five years later, Rosie visits Alex in Boston and they spend a night together talking and visiting places. The following morning, she discovers that his girlfriend is pregnant. She understands that Alex's living situation was not proper and tries to discuss it with him, but he rebuffs her, saying that at least their kid is going to have both parents. Infuriated, Rosie leaves Boston immediately. She reconciles with Greg, who had initially fled to Ibiza upon learning of her pregnancy, and eventually the two marry. She later learns that Alex split from his girlfriend after discovering that the baby wasn't his. When Rosie's father dies, Alex attends the funeral of Rosie's father and reconciles with her, whereas Greg behaves immaturely at the funeral.
Rosie bumps into Bethany, now a famous model, and suggests that she look up Alex on a coming trip to America. After having noted Greg's boorish behavior at the funeral, Alex writes Rosie a note saying that she deserves better and that he can be that better man. However, Greg intercepts the note and hides it from Rosie. Later, Rosie discovers that Greg is cheating on her and kicks him out. While disposing of his things, she finds the letter from Alex. She calls him, but discovers that Bethany is living with him now and the two are engaged. They invite Rosie to be the "best man" at their wedding.
Rosie gives a speech at the wedding, telling Alex that she loves him as a friend. Her daughter Katie brings a friend named Toby with her, in a friendship that is reminiscent of Rosie and Alex when they were children. During the dance, Toby suddenly kisses Katie, and Katie pushes him away and runs outside. Rosie and Alex follow her. Alex counsels her and tells her to follow her feelings with Toby otherwise she might regret it, a reference to how he has felt about Rosie. After a moment, Toby finds Katie and apologizes for what he did, telling her just to forget whatever had happened, but Katie interrupts him with a kiss. Alex realizes that Rosie does not remember the kiss which they shared on her 18th birthday and that he misinterpreted her desire to forget that night as her not wanting to be more than friends.
Rosie finally makes her dream come true, starting her own hotel. Alex is her second guest, and tells Rosie on arrival that he has ended his marriage with Bethany. He tells her about a recurring dream he has had about the two of them being together and they share a kiss.Lily Collins as Rosie Dunne
Beau Rose Garratt as Rosie (6 years old)
Lara McDonnell as Rosie (10 years old)
Sam Claflin as Alex Stewart
Tighe Wardell as Alex (6 years old)
Tom John Kelly as Alex (10 years old)
Tamsin Egerton as Sally
Suki Waterhouse as Bethany Williams
Jaime Winstone as Ruby
Christian Cooke as Greg
Lily Laight as Katie Dunne
Rose Molloy as Katie (5 years old)
Nick Lee as Herb
Nick Hardin as Joe American
Jamie Beamish as Phil
Art Parkinson as Gary Dunne
Love, Rosie received negative reviews from critics. Review aggregation website Rotten Tomatoes gives it a score of 29% based on reviews from 51 critics, with an average rating of 4.6/10.
Filming began in May 2013 in Toronto before moving to Dublin.