Arc Fatigue: The manga suffers from the usual issue with a romance story: because they have to fill 35 chapters with Will They or Won't They?, every time that it looks like Mari and Akko are going to make a little progress in their relationship, they slide back to Just Friends because they can't read each other's signals. After the school trip, they finally get over it and move into a relationship.Truth in Television: Any high-school-aged homosexual will tell you that misread signals are all too easy to come by (and moreso when you're trying to avoid the attention of your heterosexual friends).
When Akko mentions Sugi likes to apply her perfume to her waist and thighs, both Kuno and Urara blush and have an Imagine Spot of her doing so in lacy lingerie.
Urara: Sugi-san rocks. <3 Kuno: She's got it going on. <3
LGBT Fanbase: Girlfriends is one of the most popular 2000s-era yuri manga amongst LGBTQ women due to it being more of a Queer Romance work than other contemporary yuri series.
Vindicated by History: Largely forgotten in the decades after its original release, it's gained major attention in recent years since, with the rise of female filmmakers and the Mumblecore movement, it's very clearly a pioneer in both of those categories. Lena Dunham, who wasn't even aware of the film when she created Girls, was astonished to see an older film that shared the style and themes of her very modern series.
Harsher in Hindsight: One episode has Toni and Joan fall out with each other. They eventually get back together; it happens in a Church with a Gospel Choir and everything and it was quite the lovely scene. Cue the end of season 6 when they have another falling out, this time, seemingly for good.
Magnificent Bastard: Toni. Joan even acknowledged that this was why they were friends in the first place.
Joan: "You are the bitch I have always wanted to be." Toni: (Stunned, taken aback): "Oh, you're just saying that!"