Despite their mutual affection for each other, Kiara and Simba initially had a strained father-daughter relationship, due to Simba's overprotective nature. She yearned to prove to her father that she was responsible and mature, and despairs when Simba breaks a promise to her.
After reuniting with Kovu, Simba became distrustful about Kiara's growing love for the Outsider, and initially refused to allow him to join the pride. He changed his decision after Nala and Zazu reminded him about the law set by Mufasa, and begrudgingly allowed Kovu to come to Pride Rock.
When Simba and Kovu set off to speak together, Kiara was delighted and eagerly awaited their return.
She was shocked to discover her father had been injured in a trap that supposedly involved Kovu. After Simba banished Kovu, and confined her to her den, Kiara disobeyed his orders and went to find her love. She convinced Kovu to go with her to stop their families.
When Kovu and Kiara stood between their parents, Kiara convinced Simba to stop the feud and listen to reason.
Moved by Kiara's statement, Simba agreed and engaged in an affectionate embrace with Kiara. He and Nala later watched proudly as Rafiki blessed the union between Kovu and Kiara, and Simba roared alongside his daughter on the peak of Pride Rock.
In The Lion Guard, Kiara is shown to have a loving father-daughter relationship with Simba, and enjoys learning about the importance of ruling from him.
Kiara's and Nala's mother-daughter relationship is observed to be affectionate and supportive, Unlike Simba, Nala isn't overprotective of her daughter, and shows trust in Kiara's abilities. She expressed support and pride for her daughter on the onset of her first hunt, and was relived that Kiara was unharmed by the fire set by Nuka and Vitani.
After Simba allowed Kovu to enter the pride, Nala approached her mate, and they discussed the blossoming romance between their daughter and the Outsider. Later, after Simba was ambushed by Zira, Nala and Kiara stood beside him as he exiled Kovu. Nala visibly expressed shock along with Kiara's reaction to Simba's decision.
During the battle, after Vitani threw taunts at her about the disappearance of her daughter, Nala angrily lunged at the younger lioness. When Kovu and Kiara stood between their parents, Kiara convinced Simba to stop the feud and listen to reason, After Simba rescues Kiara from a ravine, Simba and Nala later watched proudly as Rafiki blessed the union between Kovu and Kiara, and Nala roared alongside her daughter on the peak of Pride Rock.
In The Lion Guard, Kiara is shown to have a loving mother-daughter bond with Nala, more or less the same as in The Lion King II: Simba's Pride, and enjoys learning about the importance of hunting and tracking from her.
Kiara has a strained sibling relationship with Kion. They do hold affection for each other, but are prone to sibling rivalry occasionally.
Unlike their great-uncle, Scar, Kion does not hold resentment or jealousy towards his older sister.
In The Trail to Udugu, Kion and Kiara learn to work together to find their mother, Nala.
Due to his death before Kiara's birth, Kiara never got to physically interact with her paternal grandfather. She appears to hold an intense amount of respect and presumably love for her grandfather, and understood that Mufasa would've never banished Kovu without hearing an explanation first.
After Simba had wrongfully/unfairly banished Kovu from the Pride Lands for supposedly leading him into a trap set-up by Zira, her father arrogantly compared himself to her grandfather, as Simba stated that he knows that Kovu is following in Scar's footsteps, as he must follow in his father's, enraged by this, Kiara puts Simba in his place, coldly stating that he will never be Mufasa; indirectly referring to the fact that Mufasa would have forgiven Kovu for his initial role in Zira's plan and would have seen that the ambush was not his fault, as Kovu had no knowledge of the ambush and was completely innocent.
Due to his death before Kiara was born, Kiara never physically interacted with her paternal great-uncle. Simba apparently told her about Scar, as Kiara states there was darkness in himself that he couldn't escape. From this, Kiara has low-esteem for her great-uncle, though not as strong as Kion's, as she's able to see the good in Kovu as a character and past how he felt Scar was part of him, unlike her father.
After hearing about the dangers of the Outlands and the Outsiders from her father, Simba, Kiara decides to venture into the forbidden territory, where she bumps into Kovu. After a brief confrontation, Kovu and Kiara are ambushed by a float of crocodiles. They mange to escape and formally introduce themselves, Soon Simba and Zira arrive and after a brief confrontation, they take their children back to their respective homes.
Years later, Kovu's siblings Nuka and Vitani set the Pride Lands ablaze during Kiara's first hunt, Zira sends her son into the mist of that flames to rescue Kiara. After reuniting, Kiara was pleased to see her cubhood friend. Their reunion was interrupted by the arrival of Kiara's parents, who greeted their daughter with relief. After a brief confrontation with Kovu, Simba initially refused to allow him to join the pride. He changed his decision after Nala and Zazu reminded him about the law set by Mufasa, and begrudgingly allowed Kovu to come to Pride Rock. As the days pass, Kovu and Kiara begin to spend time together, and their friendship blossoms into romance. With help from Timon and Pumbaa, Kiara shows Kovu the concept of fun, and they stargaze later that night. After Simba requested to speak with Kovu, Kiara was delighted and watched as the pair exited Pride Rock. Later, Kiara expresses shock at Simba's claim that Kovu was involved in an ambush set by Zira and heartbreakingly watched as Simba exiled Kovu. After Simba confined Kiara to her den, she escaped and ventured away from Pride Rock to find Kovu. After they found each other, Kiara convinced Kovu to return with her to their prides and reunite them.
After the battle, as Rafiki blessed their union, Kovu and Kiara nuzzled each other and roared from atop the peak with Simba and Nala.
Along with Zuri, Kiara and Tiifu are best friends. They enjoy learning how to hunt together, and usually spend most of their days together. Tiifu was very concerned when Kiara became trapped in a stampede set by Janja, and was relived when her friend was rescued.
In "Baboons!", Kiara tasked Tiifu and Zuri with helping her prepare for her royal duties, she expresses amused annoyance with their obsession with thati appearances, but later credits them when speaking to Vuruga Vurgga.
Along with Tiifu, Kiara and Zuri are best friends. When Zuri injured herself, Kiara sent her back to Pride Rock, while she and Tiifu set put to track gazelles.
In "Baboons!", Kiara tasked Tiifu and Zuri with helping her prepare for her royal duty, she expresses amused annoyance with their obsession with thati appearances, but later credits them when speaking to Vuruga Vurgga.
Despite their differences, Kiara is shown to have a close relationship with her father's childhood friend and guardian. She expresses annoyance at Simba's insistence that he and Pumbaa accompany her everywhere, After catching him and Pumbaa trailing her on her first hunt, Kiara expresses shock that Simba would betray her, despite Timon's gentle assurances that her father doesn't want her to get hurt.
Later, Timon and Pumbaa come across Kovu and Kiara, and they assist Kiara in teaching Kovu about the concept of fun.
Despite their differences, Kiara is shown to have a close relationship with her father's childhood friend and guardian. She expresses annoyance at Simba's insistence that he and Timon frequently accompany her.
Kiara appears to have a friendly relationship with her father's shaman, Rafiki was the one that Mufasa foretold Kiara and Kovu's eventual romance to, and though he was skeptical of the plan, Rafiki agreed to bring the two together for the benefit of the prides. He sang Upendi in order to boast their blossoming romance. This led to Kovu and Kiara reuniting after Kovu's exile, and joining together to save their families and prides.
After the battle, Rafiki blessed their union, and watched as Kovu and Kiara nuzzled each other and roared from atop the peak with Simba and Nala.
Like her relationship with Rafiki, Kiara is also shown to have a close friendship with Simba's majordomo. He helped her father warn her about the dangers of the Outlands, and the Outsiders, and during her first hunt, Zazu located her and led her parents to her location. After the battle, Zazu watched as Rafiki blessed Kovu and Kiara's marriage.
Although they aren't seen interacting in the film, Vitani was moved by Kiara's plea to Simba, and moved to stand beside her and Kovu. She later presumably watched the marriage of Kovu and Kiara.