Sixth Year

Hermione: "You said to us once before that there was time to turn back if we wanted to. We've had time, haven't we?"

Ron: "We're with you, whatever happens."

— Hermione and Ron commit to the Horcrux hunt with Harry

During the summer following the battle, Ron learned he had received sevenO.W.L.s, only failing Divination and History of Magic. Ron explained he did not mind, as he wasn't planning to take those in his sixth year, regardless. Also during that summer, Ron learned that his brother Bill was engaged to Fleur Delacour. While this annoyed his mother, sister, and later Hermione, Ron took to defending Fleur and if she surprised him, he would still take on that dumbstruck look. His soft spot for Fleur particularly annoyed Hermione, who was finding it harder to keep her feelings for him under wraps. When Ron and Hermione learned that Harry was in fact the "Chosen One," Ron was shocked and amazed, but remained at Harry's side. Ron would suffer much personal turmoil in his sixth year. Harry was namedGryffindor team captain. Ron was nervous about Quidditch try-outs, but beat out Cormac McLaggen in saves, partly because Hermione cast a Confundus Charm on McLaggen in retaliation for him insulting Ron and Ginny. He was also envious when Harry and Hermione were invited to the Slug Club, while the new Potions professor Horace Slughorn ignored him, and when he was paid attention to, he usually got his name wrong. During this time, Ron showed brief flashes of jealousy about Harry and Hermione's closeness. He would take exception whenever Hermione complimented Harry on something Ron thought was equally due to him. Ron was temporarily mollified about this when Hermione asked if he would like to attend the club's Christmas party with her, and he agreed. Ron was also worried over his sister's increasing involvement with boys, and after stumbling upon her kissing Dean Thomas, he blew up at her. In retaliation, Ginny belittled him for his complete inexperience with the opposite gender, declaring that Harry and Hermione had also snogged people. The siblings treated each other coldly afterwards, and Ron was so bothered by this — and by the revelation that Hermione had kissed Viktor Krum almost two years earlier — that he began to perform poorly in Quidditch. He also began to treat Hermione with a cold indifference, which confused her. He even offered to resign from the team. To boost his confidence, Harry pretended to pour the potion Felix Felicis into Ron's pumpkin juice at breakfast. Harry even allowed Hermione to see the vial, so she would object to the cheating. This convinced Ron that he had an edge in the game, which caused him to play excellently. However, when after the match Harry revealed it was a trick, Ron rounded on Hermione and accused her of having no faith in his abilities.

Shortly thereafter, Ron began his exhibitionist relationship withLavender Brown. Hermione, incredibly angry and hurt by Ron's vindictive actions, conjured a flock of canaries to attack him; the birds scratched Ron badly, and he and Hermione stopped talking to each other. Hermione attended the Christmas party, she had originally wanted to attend with Ron but went with his hated rival,Cormac McLaggen, while Ron snogged Lavender in public and made fun of Hermione's behaviour in Transfiguration class, reducing her to tears. By Christmas break, however, Ron was becoming disenchanted with his relationship with Lavender, who had become increasingly possessive, annoyed him with the nickname "Won-Won," and gave him a gift of a necklace that said "My Sweetheart". Hermione did not come to the the Burrow for the holidays, as she usually did, and Ron made an attempt to speak to her after returning to school, but she ignored him. In March, Ron ate chocolate that he believed to be from his birthday presents, but was in fact a gift from Romilda Vane to Harry spiked with a Love Potion. Upon ingesting the chocolate, Ron became maddened with an obsessive need to see and be with Romilda. When he was taken to Slughorn's office to get an antidote, he was nearly killed by poisoned mead intended for Albus Dumbledore. Harry managed to save Ron with a bezoar. A panic-stricken Hermione arrived at the hospital wing, forgetting her anger with him. Ron said Hermione's name in his sleep upon hearing her speak for the first time all day, and the two quietly reconciled after his near-death experience. Ron also took to feigning sleep whenever Lavender tried to visit him. His subsequent avoidance of Lavender and simultaneous spending more time with Hermione made Lavender suspicious; after she spotted him and Hermione leaving the boys' dormitories, seemingly alone (Harry was with them, but under his Cloak of Invisibility), Lavender ended the relationship, much to Ron's relief.

A little later, Ron was suitably impressed when Harry told him and Hermione how he managed to obtain the Horcrux memory fromProfessor Slughorn. A few weeks later, when Harry usedSectumsempra on Draco Malfoy, Ron lent his potions book to Harry, so Professor Snape would not confiscate the Half-Blood Prince's book. Throughout this school year, Ron had defended Harry's use of the Half-Blood Prince's book. He thought that "the prince" had a good sense of humour and that the book was essentially harmless. Occasionally, he was jealous, because the book helped Harry cultivate the favour of Professor Slughorn, but even after the incident Ron called "the prince" a genius. On the night of the Battle of the Astronomy Tower, Ron took Felix Felicis on Harry's instructions, along with Hermione and Ginny. Those three were joined by Neville and Luna, whom Hermione had summoned using the D.A. coins. While Hermione and Luna monitored Professor Snape's office, Ron and the others watched the Room of Requirement. Ron fought in the battle and survived without any major injuries, thanks to the Felix Felicis. He was shaken by his oldest brother Bill's scarring at the hands of the vicious werewolf Fenrir Greyback. Shortly afterwards, Ron attended the funeral of Albus Dumbledore, where he comforted a sobbing Hermione. He and Hermione informed Harry of their intention to accompany him on a quest to locate and destroy the Horcruxes of Lord Voldemort, forgoing their seventh year of school.