Tiana Webber (née Flynn) is a maternal aunt to Phineas and Candace, the sister-in-law of Lawrence and step-aunt to Ferb. Her sister is Linda, as they both have red hair and are named after Dan Povenmire's sisters. She marries Bob Webber during the summer. ("Candace's Big Day")
Tiana and Linda are sisters as they are very similar in appearance and are very close. They are seen going to a spa together, and Linda helps Tiana when preparing for her wedding. Linda even asked Tiana if she was ever planning on having children, after Linda receives a phone call from Candace. ("Candace's Big Day")
Tiana and Bob have traveled across the world together and get married before continuing on to the Galapagos Islands.
Tiana and Candace are very close, as Tiana promised that Candace could be Tiana's bridesmaid when Candace was 10-years-old. Tiana trusts Candace, as she lets her plan out Tiana's wedding. Tiana is also very calm and patient towards Candace whenever she starts to freak out.
Tiana appears to be very fond of both boys and even entrusts them with helping to plan out her wedding. They also seem to care a great deal for her, as Phineas seems very determined to give Tiana an amazing wedding. She is one of the few adults who knows about Phineas and Ferb's extraordinary abilities, as she was able to see their extraordinary ice sculpture of her and Bob before it was melted down.
- Tiana was named after one of Dan Povenmire's sisters. His other sister is the namesake and inspiration for Linda, so he decided to make a new character so the real-life Tiana "wouldn't feel left out". She isn't, however, named after Princess Tiana in the Disney movie The Princess and the Frog. Dan Povenmire claims this to be a coincidence.
- "Candace's Big Day" (First appearance)