Are Kathy Hilton and Kyle Richards half-sisters?

Yes indeed! Kathy is half-sister to Kyle and Kim. They share the same mother, but have a different biological father.

Who is Kyle, Kathy, and Kim’s mom, Kathleen Richards?

An icon in her own right, Kathleen Richards (AKA “Big Kathy”) grew up in Manhasset, Long Island with dreams of becoming an actress (later, two of her daughters would carry that torch). A single mom in the ’70s, Kathy’s daughters often talk about her specific brand of spunkiness.

“My mom was a strong woman, opinionated and outspoken,” Kyle told PEOPLE in 2018. “She made me feel like I was the greatest thing in the world.”

Kathleen was married four times over the years, to Laurence Avanzino (Kathy’s dad), Kenneth “Ken” Richards (Kim and Kyle’s dad), Jack Catain, and Richard Fenton. As you can see here, she bore a striking resemblance to her glamorous daughters.

In 2002, she passed away following a breast cancer diagnosis.

“She loved her girls and grandchildren more than anything in the world … always taking people under her wing,” wrote Kim in a March 2017 Instagram tribute on the 15th anniversary of Big Kathy’s death. “There is not a day that I don’t think of my mom and wish she was still here. But I do know she is watching over all of us … and gives me peace knowing she can see all the good that is happening in our lives.”

In 2019, Kyle had a mammogram on RHOBH in honor of her mom. “I lost my mom to breast cancer in 2002. The fact that she hadn’t had a mammogram in 5 years haunts me,” she shared on X (formerly Twitter). “I really wanted to show this to bring awareness re early detection and as a reminder to get checked.”

Who is Kyle Richards’ dad?

Kyle’s dad’s name is Kenneth Richards. A retired lieutenant colonel, he passed away in 1998.

“He was the kind of dad that would ask what we wanted to do and if we said, ‘camping!’ He would say, ‘ok, come on, let’s go’ no matter what we said he would drop everything and take us,” Kyle explained in a June 2017 Instagram tribute to her father.

Kenneth is also the father of Kim, while Kathy’s biological father is Kathleen’s first husband, Laurence Avanzino (who passed away in 1997).

Kathy, Kim, and Kyle grew up in Los Angeles

Early on in their youth, Big Kathy packed up her girls and brought them to Beverly Hills. “My childhood was different than the average child,” Kim explained during Season 1 Episode 1 of RHOBH, giving a breakdown of her career as a child actor. “I was quite famous.”

Kyle had a similar story to share.”I started acting when I was three years old. As my mom used to say, I started very late, because my sister Kim started at 6 months old,” Kyle explained in the same episode.

Later in the season, Kim shared that Kyle was like her “baby” when she was younger. “I took care of her,” she said. “And over the years, she’s become protective over me.”

Kyle Richards Reflects on Sibling Rivalry with Kim and Kathy as Kids

While appearing on the March 2024 episode of the Let’s Talk Off Camera with Kelly Ripa podcast, Kyle candidly discussed her childhood and relationship with her mom. During the conversation, she revealed how her daughters’ relationship is different than the one she had with Kathy and Kim when they were kids.

“They [my daughters] could not be more different than my sisters and me,” she said on the podcast appearance. Kyle went on to reveal “some mistakes” her mom made by constantly comparing Kathy, Kim, and her to one other. “I do remember her like saying, ‘Why don’t you do this like so and so?’ To Kim, ‘Why don’t you do what Kyle does?’ Things like that,” Kyle said on the podcast.

RHOBH Season 1 premiered in October 2010 with some sister friction

Both Kyle and Kim were original cast members on RHOBH, and it wasn’t easy working together.

“Has it been hard for you to have your relationship magnified on reality TV?” asked Andy Cohen during the Season 1 reunion. “Yes,” said Kim through tears. “I feel at times she’s a little too hard on me, and I’m very sensitive. I love her and I don’t want to fight with her. She’s the last person I want to fight with in the world.”

During the Season 11 reunion (we’ll get there!), Kathy commented on how she felt watching her sisters fight on TV. “I kept thinking about my mom, like, ‘What would my mom do?'” she recalled. “And as the oldest sister, I feel, like, [a responsibility].”

A major sister argument was showcased in the Season 1 finale

Does “you stole my goddamn house!” ring a bell? During the Season 1 finale, which premiered in 2011, Kim and Kyle got into a major fight in the back of a limousine. In the heat of the moment, Kyle called Kim an “alcoholic” and told her to get help.

“I don’t know if I’ll ever be able to talk to her again,” said Kim in an interview after the fight.

During the reunion, Kyle admitted she’s sometimes a bit too tough on her sister.

“We’re sisters. We’ve been through everything together,” Kim added. She also explained that, while they didn’t talk for a while, they were trying to repair their relationship. “I love her no matter what. In a heated moment, things are said and done that you just want to take back and you can’t.”

Kim Richards went to rehab in December 2011

After Kim admitted on the RHOBH Season 1 reunion that she struggles with alcohol abuse, she entered rehab. A few years later, she explained that being on the show — and having her issues become public — was ultimately a good thing for her.

“My decision to go back to work and live my sobriety out in the public, and live it out on [RHOBH]…the feeling of getting to go to work, and feeling important, that they needed me, it felt so healthy and good to get back out there. It just felt wonderful. Very important,” she told Dr. Sophy, the Medical Director of the LA County Department of Children and Family Services, on a 2014 episode of her podcast House Call with Dr. Sophy. “When I’m not working, I don’t feel good. I don’t feel…I’m not needed. I need that responsibility. It definitely makes a difference when you love what you’re doing and you like the people you’re working with. I like my producers, I like my crew, I like the girls…most of the time.”

Kyle Richards and Kim Richards’ complicated dynamic was shown during RHOBH Season 5

Season 5 — Kim’s last as a full-time ‘Wife — was a hard one for the sisters. Next to multiple in-season fights (the house was brought up once again), they went a time without speaking at all.

Kim Richards didn’t return for RHOBH Season 6 in December 2015

When RHOBH returned to our screens after that dramatic reunion for Season 6, Kim wasn’t among the women holding diamonds. She had stepped away from reality TV to handle some personal issues, including two arrests and seeking treatment for substance abuse

“It felt really weird starting the show this season without my sister. We started this together and she’s a very big part of the show and, obviously, apart of my life,” Kyle told The Daily Dish at the time. “It felt very strange, but the timing just wasn’t right because she was taking care of herself, and, so, it took some getting used to.”

Kyle Richards began developing American Woman in June 2015

In June 2015, Kyle announced she had a new show in the works. American Woman was a scripted series that featured a fictionalized version of Big Kathy and her experiences as a single mom in the 1970s. Two years later, Alicia Silverstone was attached to the series and the cameras were rolling.  ​​

“American Woman is the pilot I just shot, and it just got picked up for 12 episodes,” Kyle explained in a 2017 interview with The Daily Dish. “It is my first job as a television producer. I’m not in front of the camera — at all.”

Unfortunately, the show (which was canceled after one season) caused some drama with the sisters, who weren’t thrilled about how it might depict their mom … even though it was only loosely based on their experiences.

“I don’t think my sisters really understood what it was in the beginning,” she added. “I was like, ‘It’s not a reality show, it’s a scripted show inspired by [our childhood].’ The first announcement said it was a dark comedy, which kind of implied it could be sketchy or something. There’s moments, obviously… I didn’t have a traditional upbringing, which is very obvious in the show. But you know, it’s just going to be a fun show. I’m not here to torture anybody.”

Nicky Hilton uninvited aunt Kyle Richards from her wedding in July 2015

While she ultimately ended up attending the glam affair, there was a time when Kyle wasn’t welcome at her niece Nicky Hilton’s wedding to James Rothschild. (Nicky is Kathy’s daughter, FYI.)

“I was told it’d be better if I didn’t come to the wedding,” explained Kyle during Season 6. “I’ve always been very close with all of my nieces and nephews, but somewhere along the line, something happened where I was told it may be a better idea if I didn’t come.”

In the same confessional, she gave an update on her relationship with Kim and Kathy: “I don’t even know how to describe — nor do I want to describe — the relationship between my sisters and me. It’s just really bad.”

Kyle Richards and Kathy Hilton weren’t on speaking terms in May 2018

Kyle revealed she hadn’t talked to her big sister in eight months during the Season 8 reunion. The cause of all the tension? American Woman, of course. And a bit of career drama — Kyle’s husband, Mauricio Umansky, had left the family real estate company to start a business of his own: The Agency.

The Richards-Hilton sisters spent time together in September 2018

There’s nothing like a party to bring everyone together. In September 2018, all three sisters got together to celebrate Kim’s birthday.

Kathy Hilton joined RHOBH in May 2021

In May 2021, things got very interesting (especially for anyone invested in Hilton/Richards sister drama) when Kathy joined RHOBH as a friend.

“It was a wonderful experience,” she told The Daily Dish about her first season on the show. “I went on a few different times [previously], but it was always in a very serious way. I think the fans always thought I was a bitch or something, you know? I just thought this is an opportunity to spend some time with Kyle.”

Andy also shared his thoughts on having the icon in front of the camera during an episode of Watch What Happens Live with Andy Cohen.

“This season is super dramatic, but it is also so funny due in large part to one Kathy Hilton, who is a trip that I don’t think any of us expected,” he said. “I thought that Kim Richards was the motherlode of kind of lunacy, but Kathy is her own vibe, man. Kyle, I didn’t expect it.”

Kathy Hilton and Kyle Richards discussed their dramatic relationship during the Season 11 reunion

After talking through the American Woman drama during Season 11, Kyle and Kathy further discussed their relationship on the reunion couch. The episode aired in October 2021.

“When you can stand back and look at yourself by having this on the show like that, if it can help more people pick up the phone or just be more vulnerable and not waste time and a relationship,” explained Kathy. “Because we did, we wasted a lot of time.”

Kathy Hilton and Kyle Richards had another falling out in 2022

During Season 12 of RHOBH, another feud strained Kyle and Kathy’s relationship. During a cast trip to Aspen, drama broke out when Lisa Rinna (who had also had drama with Kim!) chose to drink Kendall Jenner’s 818 tequila over Kathy’s tequila brand, Casa Del Sol. When Kyle tried to calm the situation, Kathy grew upset that she didn’t try to back her up.

“Once Kathy is mad, it’s hard to turn that around,” Kyle explained in a confessional. “Listen, Kathy can be so much fun and funny. She can also be very difficult. The part that bothers me so much is how much I let it affect me. That’s where it’s different with friends versus sisters. [ … ] I really, honestly believed that we would never go to a bad place ever again. And I don’t know how I can fix this.”

Kathy Hilton and Kyle Richards saw each other in March 2023

Early in 2023, the sisters were spotted hanging out together at Elton John’s Oscars party.

Kathy Hilton and Kim Richards shared insight into their relationship ups and downs in April 2023

“I look up to you … You’re like my biggest supporter,” Kim told Kathy during an interview with Entertainment Tonight. “You’re always behind me and always encouraging me and when I think I can’t do something, I know you believe I can.”

The Richards-Hilton sisters officially reunited in May 2023

Together at last, Kathy, Kim, and Kyle got together at Kim’s daughter Whitney Davis’s bridal shower in May 2023. The next month, they once again spent time together at the wedding.

Still, everything wasn’t always peachy surrounding the nuptials. At one point, Kim was conflicted about Kyle attending the event because of her relationship with Kathy.

“I think that what I’m saying is I don’t want anybody coming there that isn’t in a good place with somebody,” she explained during Season 13, Episode 10. “I would always be — I mean, obviously I haven’t seen Kathy; well, actually, I saw her at the Elton John Oscar party — but I would always be polite, always be nice,” Kyle responded.

Kathy Hilton stood by Kyle Richards during the RHOBH Season 13 reunion in March 2024

All seemed to be better by the time the Season 13 reunion was filmed, where Kathy showed up to support her baby sister amid her ongoing separation from Mauricio.

“I wanted to be there and just hold her hand,” Kathy told ET after filming. “I wanted to be there and be supportive. It was great to see all the girls again.”

Kyle also had something nice to share about her relationship with Kim during the season. “Kim’s and my relationship is in a very good place,” she said in a confessional during Season 13 Episode 7. “She knows I’ve been going through a really hard time and she’s been very supportive this last year.”

Kathy Hilton and Kyle Richards spent plenty of quality time together in 2024

2024 seems to be a good year for the sisters. In February 2024, Kyle and Kathy had a girls’ night out walking the green carpet at the 2024 People’s Choice Awards with their fellow RHOBH cast members. They were also seated together during Sutton Stracke’s fashion show for Her Sutton Brands Green Label Capsule Collection in July 2024.

Is Kyle Richards currently talking to her sisters?

As of right now, all seems to be well in the world of the Hilton and Richards sisters.

“We’re great, thank God,” Kyle shared during BravoCon 2023. “You know we’re really good. We talk every day.”