Balin is Thorin's trusted advisor and father figure and both had a great deal of care for one another. They have been together since Smaug invaded Dale and Erebor and stole the .In Bag End, Thorin relies on Balin's support, and is glad to have him in his company. However, sometimes Thorin did not listen to Balin in the first part of their journey, such as ignoring Balin when the dwarf tried to dissuade him from giving Elrond the map.
Despite all of this, Oakenshield trusted Balin more than anyone, as he allowed him to lead the company on the familiar roads only the old dwarf knew and also told Balin what he told Thranduil. Thorin was also fiercely protective of Balin, saving his old friend from an Orc that nearly killed him. Thorin also trusts Balin will keep Bilbo safe from Smaug, as he instructs the hobbit to follow Balin and leave him to his fate.
When Thorin fell into gold sickness, he did not care about Balin at all and only himself and kept trust in Bilbo rather than the rest of their friends and also yelled at Balin and his brother for failing them. However, Balin follows him to Raven hill before he tells Dwalin, Fíli and Kíli to leave him. His death affected Balin and those around him, stating that Thorin will pass on into legend but he would be well remembered.
Thorin first met Bilbo when Gandalf introduced them in Bag End. However, he openly ridiculed Bilbo at first and proclaimed that he would not be responsible for Bilbo, but he did save Bilbo at least twice: once from the Trolls and a second time from falling off a cliff. Thorin's view of Bilbo immediately changed, apparently after he said he was helping them find their home out of pity, and after he saved Thorin's life from Azog's executioner.In gratitude for saving his life, Thorin hugged Bilbo and apologized for his poor treatment of him earlier. It is also noted that Thorin always referred to Bilbo as "Master Baggins" rather than his first name.
After this, Thorin and Bilbo's relationships as friends improved, proven when Thorin was concerned when Bofur reported Bilbo missing when they were captured by elves. After being imprisoned by Thranduil, Thorin trusted the hobbit was their only hope and even agreed with Bilbo for using barrels as an escape and half-surprised Bilbo had aggressiveness in him. Thorin was not acting himself, becoming cold and remorseless for Bilbo to get burned alive by Smaug. However, Thorin's good nature overcame him and decided to save Bilbo a second time, with the dwarves aiding Thorin. During their final confrontation with Smaug, Thorin finally acknowledged Bilbo by his first name, addressing him as a friend rather than a stranger.
During the Battle of Five Armies, Thorin and Bilbo had a strained relationship again. Bilbo was shown to be extremely worried about Thorin, especially learning of the gold sickness that hurt him just like his grandfather before him and was willing to protect his friend from falling into the madness further. After learning Bilbo stole the Arkenstone, the two of them exchanged angry words with each other, and Thorin nearly killed Bilbo over it. This wasn't the last time they would see each other as friends, as upon seeing Bilbo again since their last departing did not go to well, Thorin was shocked and relieved to see his friend again and later appeared remorseful for what he did to Bilbo on the gate. When Thorin was dying, he comforted Bilbo and said that what he did was only doing something a friend would do and admitted he was too blind to see it.
- "You were always my King. You used to know that once. But you cannot see what you have become."
- —Dwalin to Thorin Oakenshield[src]
Dwalin is Thorin's best friend and partner-in-crime once in a while.
Together, they were raised side by side and became the best of friends and were like brothers. However, during Thorin's reign and gold sickness, Dwalin began seeing a different person and not the one he once knew. Sometimes, Dwalin doesn't bow to Thorin because they've been best friends.