What is the secret of Aria in Pretty Little Liars?

Answer 1

She was bulimic.
Hannah has many secrets. Her mom stole money from a bank, she pushed WIlden's car into a lake, she shoplifted, she had bulimia, was present the night that Alison's body was stolen, she was a part of Jenna being blind, she kissed Wren, Saw Alison three days before her disappearance, she is actually very smart, the things that happened to her at the dollhouse, She killed Elliot Rollins, Secretly broke up with Jordan, and she abducted Noel.
She is a thief
Well, here's a clue...watch it until the end. They will reveal it, just maybe not yet.
She made herself throw up to get thin
she has bulimia

Answer 2

it depends if you mean the books or the TV series? her secret was, until revealed to her parents, that she's in a relationship with her former English teacher. They both met each other before they knew everything about each other. This is her main secret from the TV series.

Answer 3

she makes her self throw up to lose weight and when she is in the middle of doing that Alison walks in on her.

Answer 4

She can really see.