Rhonda is very spoiled, vain, greedy, cowardly, arrogant and sassy. She thinks highly of herself and her whole family. In addition, Rhonda is very pathetic, because if something bad happens to her, she often makes a big deal out of it, like it's the end of the world. As a result, she gets on everybody's nerves, especially when it comes to her fancy trinkets. However, Rhonda is somewhat nice to her best friend, Nadine, with whom she often disagrees. However, she has displayed occasional empathy and concern for her friends, though even this is usually triggered by personal strife (i.e. "Cool Party, Rhonda's Glasses, Curly's Girl).
Rhonda always wears her red sweater with white collar and long black pants. Though Rhonda always wears shoes that are red, the style of shoe changes from episode to episode (some times scene to scene). Most often Rhonda wears healed slip-ons, but she also wears pointed flat boots that cover her ankles. Other times she can be seen in simple red shoes with white soles or simple red shoes with black soles. She has short black hair with bangs that cover the top of her eyes. In Hey Arnold! The Jungle Movie, Rhonda is more physically developed, and now wears a red jacket, gold necklace, a long blueish shirt and the same black pants.
As one of the students of P.S. 118, Rhonda is the self-proclaimed fashion queen of the school, despite the fact that she, like all the other main characters, wears the same ensemble each day with few exceptions. Her parents, Brooke and Buckley, come from a historically wealthy Welsh-American family ("The Lloyds"). Throughout the series, Rhonda hosts a number of parties at her house (Helga's Makeover, Hey Harold!, Cool Party, Helga's Masquerade). One of the main surprises would be with all the LLoyd's proclaimed wealth, Rhonda attends a state school and catches the bus, where as Lorenzo and Rex Smyth-Higgins III are seen in limos as well as live in extremely luxury homes - Rhonda seems to live in a average town house, not particularly bigger than any of the other characters' homes.
Rhonda's role in Hey Arnold! was initially as an undefined, neutral side-character who appears in the background and rarely speaks, but in the midst of the second season, when she had her first major starring episode in "Rhonda's Glasses", she was revealed to be very narcissistic and self-absorbed. Specifically, she brands herself as "popular", and her more socially-awkward peers as "geeks" and bars them from sitting near the front of the bus (as a parody of the historic 1955 Rosa Parks incident). Despite her coming to terms with her social outcasting by the end of the episode, she returns to it again in "Cool Party", making it an almost formal practice by composing a mutually-exclusive list of "Geeks" and "Cool Kids" to decide who can and cannot attend her house party.
Among other humbling life experiences Rhonda is pitted against, there is a point where her family loses their entire fortune in the stock market, forcing her to adapt to a lower-middle class standard of living in Arnold's boarding house ("Rhonda Goes Broke"). Her materialistic mentality translates it to a miserable, doomed experience that she spends days moping over (even worse than her parents, who seem to have some understanding of low-income life), which disgusts Arnold and prompts him to tell her to change her attitude. As in "Rhonda's Glasses", she makes the best out of the situation and pulls through it.
Nadine is Rhonda's best friend. Although the two have many differences and appear to get into arguments quite easily, notably because Nadine is an aspiring entomologist whereas Rhonda's interest lies in fashion, they are seen in multiple episodes associating with one another.
Rhonda's greatest interest is fashion design and trends. She criticizes her classmates and friends regularly for not matching colors or rotating their daily choice of clothing, as parodied by Helga in "Helga's Show". She is also quick to show off any new fashion accessories or shoes she gets to her peers. As shown in "Rhonda's Glasses", she requires glasses to see, but after that episode she switched to contact lenses ("Rhonda Goes Broke").
Despite her wealthy upbringing and snobby, self-righteous attitude, she has been known to play contact football and a variety of other sports along with the other children — even to the point of destroying her beloved outfits in the process, as seen in "Mudbowl" and "New Bully on the Block". She is a formidable football player as well, scoring 3 touchdowns and accounting for 18 of the 48 points scored against the 5th Graders in Mudbowl. She also participates in various neighborhood baseball games and in other sporting events such as the city bowling tournament ("Coach Wittenberg") and Bikeathon ("Gerald's Secret").
There are implications in the series that Rhonda might be/have been romantically interested in Harold. In "Operation Ruthless", Rhonda is seen pulling Harold to the Love Tunnel's boat while saying "I know you like me, Harold", as Harold tries to resist. Then in "Love and Cheese", for a brief second when Arnold and Lila are in line to the Tunnel of Love, you can see Harold and Rhonda sitting together in the duck. Later, in "Egg Story", Rhonda and Harold are assigned to work as a couple to take care of an egg. When Harold reminds her about their moment in "Operation Ruthless", Rhonda nervously smothers his mouth with her hand to prevent him from talking, which either could mean she wants to keep it secret, or that she regrets that night.
There are also hints that there may be chemistry between her and Sid, in the episodes "Wheezin' Ed", "World Records", "Fighting Families", "Rhonda Goes Broke", "Arnold's Room", and "Stuck in a Tree"; although these are even more subtle and ambiguous.
It's been more or less hinted that she may have feelings for Arnold, as she is really nice to him and seems to care about him more than other boys, such as in "Best Friends", "Cool Party", "Dino Checks Out" and "Beaned". She also didn't mind having to kiss Arnold when she was cast as Juliet in "School Play" before Helga manipulated her into dropping out, and called him a very nice boy in "Arnold & Lila". Rhonda and Arnold are seen dancing together in "School Dance", plus she gives Arnold a tip for helping her to accept the life of not being rich in "Rhonda Goes Broke".
Rhonda is the object of Curly's obsessive affection, much to her chagrin. In the episode "Curly's Girl", he essentially blackmails her into pretending to be his girlfriend at school for a week. She is also harassed or pranked by him constantly throughout the series. Some examples of Curly's inappropriate advances can be seen in "The Flood" and "Deconstructing Arnold", where he exclaims "give Daddy some sugar!" He has also kissed Rhonda more than once by surprise, horrifying their surrounding classmates each time. Despite all this, and her blatantly animated disgust toward him, Rhonda still says she thinks "he's an okay guy." Curly is also Rhonda's tango partner at the dance in "April Fool's Day". One possibility is that Curly's crush on Rhonda came out after her upstanding behavior in "Rhonda's Glasses".
- Rhonda, along with lead character Arnold, Helga, and Harold, was one of the first characters created for the series, even preceding Gerald. And after becoming much more prominent in the series from "Rhonda's Glasses" onward, Rhonda ended up appearing in more than half of the Hey Arnold! episodes. Besides Arnold, Gerald, Helga, and Grandpa Phil, she had perhaps more speaking roles than any other character, at about the same level of prominence as Harold and Phoebe.
- Rhonda attending P.S. 118, participating in sports, and having a normal house in spite of being rich are all most likely just a result of those things being established before she was turned into a popular, spoiled, fashion-obsessed rich girl starting with "Rhonda's Glasses".
- The shape of her head became rounder over the course of the series.
- She and Nadine have been best friends since they were in preschool.
- Rhonda, like Arnold, is left handed.
- "Lloyd", Rhonda's last name, came from Helga's taunt to Rhonda in "Arnold's Christmas", according to Craig Bartlett in a chat.
- "Wellington" is Rhonda's middle name, and not part of her last name, as she's referred to just as "Rhonda Lloyd" several times.
- In the Polish translation of the series, this character is named "Olga Wellington," and therefore shares the same first name as Helga's sister.
- In the Hungarian dub some episodes had Rhonda's name changed to Rozie because "Ronda" means ugly in Hungarian.
- Rhonda knows how to sew, as seen in the episode "Rhonda Goes Broke".
- Rhonda's ears are slightly crooked in "Rhonda's Glasses", indicating she has some deformity, likely an off-track skeletal axis.
- According to Arnold in "The Racing Mule", Rhonda had at least one pony at a birthday party of hers that Arnold had attended when he was five.
- In Hey Arnold! The Jungle Movie, Rhonda's hair is shown to be sensitive to humidity.