Lorelai and Rory Gilmore are known as the mother-daughter duo who share everything - they are best friends as well as mother and daughter. Except, of course, they don't always tell each other everything. They often hide things from each other, even before the big fallout that led to them not speaking until Rory went back to Yale.
They aren't the only ones, either. A lot of the Gilmore Girls characters spend the show carrying around some heavy secrets. Most of these also come out, in the end, and it always causes drama - whether that falls on the person keeping the secret, or the person who finds out about it. But what were the biggest secrets in Star's Hollow?
Lorelai & Max Hid Their Relationship
When Rory was going to Chilton, Lorelai began a relationship with her teacher, Max. Unsurprisingly, the two had to keep their relationship a secret, because if the other parents knew that Rory's teacher was dating her mother, there would be accusations of favoritism (among other things). However, the pair didn't do the best job of keeping that secret. While they managed to hide it from the school for a while, eventually, they were caught kissing in the classroom. Carelessness on their part, and of course, it caused quite the Chilton scandal.
April's Mom Kept Her Existence A Secret
In season 6, Luke was astounded when a young girl came to the diner, looking for a hair sample so she could run a DNA test for her science fair project - which was to find out who her biological father was! Luke eventually discovered that an ex of his had been keeping his own child a secret from him for over a decade, which is a huge secret to begin with. On top of that, Luke's struggle to figure out how to be a father, and how to deal with parenting conflicts with April's mother, ended up breaking up his relationship with Lorelai, giving this an even bigger impact.
Richard's Lunches With Pennilyn
After bumping into Richard's ex, Pennilyn, at a Yale event, Emily learned that Pennilyn and Richard were not as out of touch as she had thought. They had been having lunches together every year, and Richard kept it a secret from his wife. Emily was, unsurprisingly, devastated.
It wasn't just the lunches, although she found that strange, but the fact that her husband had been lying to her their entire marriage. This ended up being such a big lie that it was part of one of their biggest fights.
Rory's Affair With Dean
Long after Dean and Rory broke up, and Dean had married someone else, the pair ended up sleeping together - hardly a great move on either of their parts. Rory and Dean managed to keep their affair secret for a short while, but after Lindsay found a letter Rory wrote telling Dean they would have to end things, the cat was out of the bag. Lindsay was furious, and kicked Dean out (eventually divorcing him over it). Their marriage would likely have ended anyway, but this was the secret that was the final straw.
Jess's After School Job
This is a surprisingly wholesome secret, at first - as Jess gets an after-school job at Walmart, and keeps it a secret because it's not cool enough for his image (and because Jess doesn't tell people anything as a general rule). Even after Luke finds out about it, though, Jess lies about the extent of his work hours. He claimed to just be working part-time, but is actually a full-time employee, and his job ends up taking so much time away from school that he doesn't graduate. The resulting fallout with Luke and Rory is what pushes Jess to leave town, making this one of the most dramatic secrets in the series.
Lorelai Hid Her Financial Situation
Lorelai hides the details of her life from her mother as a matter of principle, and when her house needed work done to deal with termites, it was no exception. Eventually, Rory told Emily about the situation, and Emily did help Lorelai secure the money that she desperately needed, but this is just one example. Throughout the show, Lorelai keeps secrets from her mother, believing (often correctly) that her mother would use the information against her if she knew.
Rory & Marty Pretended They Didn't Know Each Other
Marty can take the lion's share of the blame for this one, as when his girlfriend 'introduced' him to Rory, he pretended that they had never met before - even though they had once been quite close friends.
Rory then went along with the secret, and it all came to light when Logan revealed the truth, uncomfortable with the lie that had - by then - been going on for a little while. This was a particularly strange lie, too, as there was no reason that it would have been odd for the two students to know each other. In the end, this secret led to Marty's breakup, and Rory losing a friend.
Lane's Entire Life
Lane is probably the most accomplished secret-keeper in Star's Hollow, as for most of the series, she is able to hide almost everything about herself from her strict mother. She hides CDs under her floorboards, has an entire secret 'rocker' closet, hides her clothes under her 'approved' clothes, and even manages to hide her band and her boyfriend from her mother for a while. Of course, in the end it all comes out - and for the best, as Lane is able to build a better relationship with her mother and live the life that she wants, but it's still a huge secret to keep, especially for so long.
Rory's Affair With Logan
The secrets continue into the revival, A Year In The Life, and they just keep getting bigger. It was a shocking moment when fans realized that Rory was sleeping with Logan again - but a bigger one when it became clear that Logan is engaged (to someone else), and that they are keeping the entire thing secret, from everyone. Compared to this, her affair with Dean was nothing, and it seems that by the end of the revival, this is a secret that hasn't yet come out.
The Secret Bar
The other big secret in the revival is the 'secret bar' - a bar that exists in Star's Hollow, and that everyone knows about... except for Taylor Doose. It's not really revealed how this works (beyond everyone having to collapse their chairs and hide if he walks past), and it seems to be played essentially just for laughs and a reference to how uptight Taylor is. Still, it's impressive that the entire town could come together and hide a bar!