Simba and his father had a strong father-son relationship. Simba looked up to Mufasa in every way, and after being chased by the hyenas, he said he was just trying to be brave like him. Mufasa then teaches Simba the proper conduct in times of danger and as a king, and discourages him from taking foolish risks. Simba spent all the time he wasn't with Nala with his father, and Mufasa showed him how to be a good ruler. When his father was killed in the wildebeest stampede caused by the hyenas under Scar's signal, he was grief-stricken, believing it to be his own fault. It was Mufasa's spiritual guidance that eventually convinced Simba years later to reclaim the throne stolen from him by his diabolical brother.
In the second film, it is shown that Simba desires to live up to his father's legacy. Several of Simba's actions are based on what he thinks his father would've approved of and done.
Simba's mother, as well as the queen of Pride Rock and the mate of Mufasa, Sarabi and Simba have a loving mother-son relationship. She was proud of her son, and like Mufasa, tried to teach him proper conduct and groomed him for his future as the king. She was also protective of him, ensuring that Simba didn't run off to where he could get himself into trouble. When Scar claimed that Simba died alongside Mufasa in the wildebeest stampede, she was heartbroken. Years later, when Simba arrived to save his home, he watched in horror as Scar berated his mother. When Scar struck her down in a fit of rage, Simba immediately came to her defense and comforted her. After assuming him to be Mufasa at first, she was in disbelief to see her son alive, but very elated. After Scar was forced to confess that he killed Mufasa, Sarabi fought by Simba's side and they managed to save their home and avenge her murdered mate. She watched proudly as Simba assumed his throne as intended.
As a cub, Simba loved his uncle, and would always tell him of his adventures, but Scar never seemed to be even remotely interested, due to his jealousy of his nephew's royalty status as next in line for the throne. After Simba tells Scar about his father showing him the whole kingdom, Scar deliberately told his nephew about the Elephant Graveyard, hoping that Simba would go there and get himself killed (even though he covered his mouth and pretended he told him by accident).
Scar sent the hyenas, Shenzi, Banzai and Ed, after Simba to kill him, but this first attempt failed. Later on, Scar led Simba into a deep gorge, and Scar, along with help from the hyenas, caused a stampede of wildebeests in the gorge, intending to kill Simba and his father. He only succeeded in killing Mufasa, his older brother, by throwing him off a high ledge he was clinging on to and into the stampede. He lied to Simba into believing that it was his fault, and that he should run away and never return. Scar then again ordered the hyenas to kill Simba, but they failed once again, unbeknownst to Scar.
Years later, Simba is now a young adult, and he went to challenge Scar for the throne. He saw Scar slap Sarabi (Simba's mother) across the face. Thus, Simba's love for his uncle turned into pure hatred, and he told Scar to either step down or fight. Scar said that he would step down, but he can't since the hyenas thought he was the King. Then, Scar made Simba reveal that he's responsible for Mufasa's death, but Simba insisted that it was an accident and that he's not a murderer. Just as Scar was about to throw the "murderer" off Pride Rock, he whispered to Simba and told him that he killed Mufasa. In his rage at Scar for being a liar and a murderer, Simba jumped back up and pinned his uncle to the ground calling him a murderer and forces him to admit what he really had done to Mufasa to the lionesses. After Simba forces Scar to reveal the truth to the lionesses, a violent fight between the lionesses, Timon, Pumbaa, Rafiki (who all appeared to aid Simba), and the hyenas ensued. Simba then chased Scar up Pride Rock on his own, and soon cornered him in an attempt to overthrow him. Scar, knowing he wasn't strong enough to defeat Simba, begged for mercy and even tried to blame everything on the hyenas. Simba refused to believe him, piinting out that everything Scar ever told him was a lie. Simba, not wishing to become the monster Scar was, spared him instead of killing him, telling him to run away and never return (the same words Scar told Simba when he was a cub). Scar pretended to leave, but tricked him and threw burning embers at Simba's face, and then a fight between Simba and Scar broke out. Before Scar could pounce on Simba and kill him, Simba kicked him over an edge and Scar landed down at the bottom of Pride Rock, where he was killed by the hyenas in revenge for his blaming them for Mufasa's death.
Simba hasn't forgotten how Scar ruined his life, and swore to spare his family and the Pride Lands from another such tragedy. In the second film, it is implied that maybe Simba is trying to forgive his uncle for his actions because when he takes a walk with Kovu, he simply says that Scar couldn't let go of his hate and in the end, it destroyed him.
Simba and his daughter, Kiara have a loving father-daughter relationship. Simba, like any father, tries his best to protect Kiara, but the headstrong lioness, like any daughter, doesn't always heed his orders, shown to stray from the path that her father marked for her and even entering the Outlands even after Simba warning her about it. When Kiara met the Outsider Kovu, son of Simba's hated enemy Zira, he immediately disapproved of their friendship and became overprotective of Kiara.
When Kiara is an adolescent, Simba had promised to let her go on her first hunt alone. However, he secretly sent Pumbaa and Timon to watch her like he did when she was a cub. Kiara discovered this and becomes furious with her father, and ran off to the outskirts of the Pride Lands. Angered and worried, Simba forbids her to go on anymore hunts when Kiara nearly died in a brush fire set by Vitani and Nuka, Kovu's siblings. When Kovu returned, he kept a close eye on the two friends, but eventually warmed up to Kovu when he proved himself trustworthy. Unfortunately, Zira, after learning of her son's betrayal through Vitani, ambushed Simba in a trap and deceitfully praised Kovu, when he in fact didn't see the ambush coming which almost ended up in Simba's death. After this incident, Simba forbade Kiara from so much as leaving his sight, and banished Kovu. Heartbroken, Kiara said her father would never be Mufasa, greatly hurting her father. Kiara then ran off to find Kovu.
When Simba fought the attacking Outsiders, Kiara stopped him, with Kovu's help. She finally made him realize that he and the Outsiders were one and the same, finally ending the feud, and he and his daughter finally nuzzle. When Zira attacked Simba in rage, Kiara tackles her, and Simba helped her after Zira fell to her death in the raging river below. Simba was finally able to reconcile with his daughter and accepts that she's old enough to become self-sufficient and make her own decisions.
In The Lion Guard: Return of the Roar, Simba and Kiara have a close father-daughter relationship with Simba lecturing Kiara about being future Queen.
Simba has a fairly good father-son relationship with his son. In The Lion Guard: Return of the Roar, Simba becomes annoyed with Kion when he and Bunga unintentionally disrupt his lecture with Kiara and ends up having to separate his two children when they argue. When Rafiki declares that Kion is ready to lead the Lion Guard, Simba is at first worried about this, thinking that due to Kion being a cub, he is not ready. But changes his mind when Nala encourages him to listen to Rafiki.
After seeing that Kion has chosen Bunga, Beshte, Fuli and Ono to be part of The Lion Guard, Simba is not pleased. He tells his son that the Lion Guard has always been made up of lions and scolds Kion for treating his role of leader as a game and tells him to take his responsibilities seriously like Kiara does with hers, however in truth, he is taking his duties as the leader of the Lion Guard very seriously.
However after Kion and the Lion Guard save Kiara from a gazelle stampede and chase away Janja and his clan, Simba realizes that Kion was wise to have chosen who he chose and expresses pride in his son and accepts the Lion Guard. Ever since then, Simba has helped Kion defend the Pride Lands, as seen when he helped Kion defeat Reirei and her jackal family, and, he even lead the guard temporarily while Kion was away.
Although Simba is protective of Kion, it is never to the point of being overprotective, like Simba is with Kiara.
Friends and Allies
Timon and Pumbaa have been Simba's best friends ever since he ran away after his father's death. Though it is shown in the third film that Simba had a habit of waking Timon up in the middle of the night (this happened 4 times in the film: 1st was to go to the bathroom, 2nd was to get a drink of water, the 3rd was presumably go to the bathroom again, and the 4th time being that he had a bad dream and ends up sleeping with them). He was also, according to Timon, holds the record of the world's "longest bug belch", as well as beating both of them in various bug-eating contests (Slug Swallowing, Cricket Crunching, Grub Gulping, Maggot Munching, and the shown Snail Slurping). As a cub, Simba thought of Timon as a surrogate father figure and looked up to him a lot, while he saw Pumbaa merely as the uncle he never had in comparison to Scar.
As gratitude for saving him out in the desert, Simba decided to repay them by protecting them from danger. When Simba went back to Pride Rock to save the Pride Lands from Scar's Tyranny, Timon and Pumbaa fought alongside Simba and Simba was again grateful to them for helping him (in the third film, when they bowed respectfully to him, he hugged them, and claimed that he couldn't have done it without them). While Simba is King, Timon and Pumbaa are his body guards and are often tasked by him to look after Kiara.
When he first interacted with Rafiki, Simba found him to be mildly annoying, most likely not remembering that Rafiki was the same baboon that anointed him at birth. After he helped Simba with his identity crisis and helping him in the fight against the hyenas, Simba began to regard Rafiki as a friend and ally. When Simba exiles Kovu, he sighs very sadly that Simba defied his father's paw prints.
As a cub, Simba had the habit of teasing Zazu and ditching him whenever he was asked by Sarabi to accompany him and his best friend, Nala on their adventures. As an adult and king after overthrowing Scar, Simba became more professional with Zazu, who like for Mufasa, serves as majordomo of the Pride Lands with the exception of babysitting Kiara, which was the job of Timon and Pumbaa. Zazu like Simba also didn't trust the Outsiders.
Not much is known about Simba and Bunga's relationship other than Simba often found Bunga annoying at times but has some respect for him seeing Bunga is his son Kion's best friend. At one point, Simba and Bunga began to see each other as brothers, since they were both raised by Timon and Pumbaa. Though in Simba's case Bunga can be the annoying brother at times.
Since Kovu was the son of Zira, his enemy in The Lion King II: Simba's Pride and Scar's chosen heir, at first he saw Kovu as untrustworthy and an enemy. Yet, when an adolescent Kovu saved his daughter, Simba was forced to repay his debt by accepting him and reserving any judgment. Later, when Simba took Kovu out for a walk and talked to him Scar's story, it seems Simba has begun to accept him, but when the Outsiders attack him with Zira implying that Kovu was the one to lure him, all trust Simba had for him vanished, and now saw Kovu as a traitor all over again.
When Kovu tried to speak for himself in order to deny any connection with the ambush and asking for forgiveness, Simba banished him, in spite of Kiara's protests, while stating that Kovu is following in Scar's footsteps and that he himself must "follow" in his own father's footsteps. In the end, when he sees Kiara and Kovu together, he apologizes to Kovu for arrogantly banishing him and accepts him, along with the other Outsiders, to the Pride Lands. He also watches Kovu and Kiara as Rafiki blesses them. Roaring with him on the top of Pride Rock, alongside Nala and Kiara.
Simba's best friend since they were cubs, the two were nearly inseparable. Unknown to them, they were betrothed at an early age, and both agreed that friends marrying each other was too weird once they discovered this fact. They got into many adventures, but when they were being chased by the hyenas, Shenzi was about to kill Nala and Simba saved her. Simba and Nala nearly died when the hyenas were after them they were trapped. Simba let out a feeble roar, but then, Simba and Nala were saved by Mufasa. Nala was heartbroken when Scar claimed that Simba died with Mufasa in the wildebeest stampede. As young adults, Nala was the lioness who brought Simba back to Pride Rock to put an end to Scar's tyranny. In the midst of all this, they finally realized their friendship had grown into a relationship, and eventually marriage as originally intended. As mature adults, parents, and the Queen of Pride Rock, Nala often acts as a voice of reason for Simba, trying to get him to see the light when his protective judgment gets the best of him.
Simba and the hyena trio are enemies. They have made several attempts on his life; however all of them have ended in failure. After Scar is killed by the hyenas, even though then they have stopped being loyal to Scar, it is assumed that the hyenas remained enemies with Simba, as they are not shown together in the sequel, on account of the hyenas not appearing, and in The Lion Guard, their descendants are constantly driven out of the Pride Lands by the Lion Guard.
Zira is another one of Simba's greatest enemies. He banished her and her pride to the Outlands due to their worship for Scar, threatening a harsh punishment should they return. When the outsiders came to the Pride Lands for an attack, Simba gave Zira a final chance to surrender and return to the Outlands, however, Zira refused and attacked anyways. The two lions were about to engage in a potentially bloody battle, when Kiara and Kovu intervened. While Simba was ready to call off the war and allow the outsiders to return to the Pride Lands, Zira still wanted to kill Simba to avenge Scar. Simba tried reasoning with her, but Zira refuses, which, like Scar, ultimately leads to her death.