Akaashi seems to be Bokuto's friend and underclassman. The two make a powerful spiker/setter duo. Akaashi also knows Bokuto well enough to deal with his ups and downs during games (during the Nekoma-Fukurōdani match where Bokuto forgot how to use crosses), and the two have even been seen hanging out outside of practice. Bokuto tends to ask Akaashi for praise after performing an impressive move despite the setter being an underclassman. However, Akaashi tends to decline Bokuto's requests.
Kuroo and Bokuto seem to be close friends, seeing as they are often seen pestering other people together. They have also been observed to have similar reactions to certain events, such as when Tsukishima asked them a question. Bokuto usually does extra practices with Akaashi and Kuroo, despite the latter being from another team. While the two are generally on friendly terms, they tend to have small contests against each other, though most of them are trivial; during the BBQ, they fought to see who could grab the most amounts of meat. When it comes to matches, they become full-on rivals. However, during matches they also compliment each other. For example when Kuroo said "As usual he fires up the entire gymnasium", or Bokuto says "Damn the demon cats and their godlike receives".
During the training camp, Tsukishima had developed a somewhat friendly relationship with Bokuto which consisted of Tsukishima and Kuroo blocking for the ace. However, as Tsukishima's development continued, Bokuto became a wise figure for the first year's curiosity on what volleyball meant to him.
Although Bokuto appears to be the elder brother, or pillar, of his team, he is actually the "baby" that's supported by his family. During his mood swings, his teammates are usually responsible for caring for him, cheering him up, etc. However, they do trust him to bring himself back into the game just as how Bokuto trusts them to support him.
Despite that, his teammates tend to desert the ace whenever he has his spiking practices due to them being endless.
Bokuto is also close to the manager, who he borrows money from sometimes (though he usually forgets to pay her back).