In #FeministSF on Twitter, the subject of science fiction for girls came up. And it has to be said, the titles kept veering back into fantasy. So here's me doing something about that.
I'm not going to try and define what makes a science fiction novel 'for girls', what counts as a strong female character or any of those issues. I've gone for the simple criteria of books where the main character is a girl. Or for ensemble books, where at least one of the main characters is a girl (though I've been pickier about including those).
One reason for keeping it simple is the big issue is still the attitude that science and science fiction isn't for girls/women. And it doesn't take much more than seeing a few female astronauts to turn "only boys can be astronauts" into "everyone can be astronauts".
The books range from classics in the genre to new releases, ordered by year of release. Just in case anyone thought girls doing science fictional things was new.

1. Outside - Andre Norton (1974) - Kristie lives in a sealed city where there aren't any adults, and she's determined to find out what is outside. [Post-Apocalyptic, Middle Grade]
There are lots of Andre Norton books that could go here. This one is interesting, as it's clear how similar elements appear in later books on the list.
2. Dragonsong - Anne MCCaffrey (1976) - Menolly's musical talents aren't appreciated at home, so she runs away to live in the wilderness. [Science Fantasy, Young Adult]
Though a lot of McCaffrey's books are accessible to older children and teens, the Harper Hall of Pern series was written specifically with young adults in mind, and has a teenaged protagonist. The sequels are Dragonsinger (1977) and Dragondrums (1979).
3. The Voyage of QV66 - Penelope Lively (1978) - The humans left for Mars after the floods, leaving the world to the animals. The other animals all know what they are, except for Stanley. After seeing himself on a advert for London Zoo, he and his friends head off for London to find the answer. [Post-Apocalyptic, Middle Grade]
I've mostly gone for books with humans. I made an exception here as it's a fun concept. It may be a way of introducing a child to science fiction, who has previously thought it wasn't for them. The animals are mixed male and female.
4. Earthseed - Pamela Sargeant (1983) - Zoheret and her shipmates have been raised by Ship, as colonists for a new world. Their final challenge before colonisation is surviving in an artificial Earth habitat. But things don't go entirely to plan. [Space Travel, Young Adult]
I found the relationship aspects in this worrying as a tween, as I felt she ended up in an abusive relationship. But it wasn't glorified as super romantic the way modern YA often does, so in hindsight, it's probably not any worse.
There are apparently sequels: Farseed (2007) and Seed Seeker (2010). I've not read them. It took me a long time to track this book down actually, as I was convinced the main character was called Sarah. This made searching for it difficult. Ah, dyslexia. Where characters are named whatever your brain decides to call them, not the actual combination of letters on the page.
5. Children of the Dust - Louise Lawrence (1985) - Sarah runs home from school, to help her family prepare for the bombs dropping. After the attack, she cares for her younger brother and sister. When she and her brother show the symptoms of radiation poisoning, she has difficult decisions to make. [Post-Apocalyptic, Young Adult]
This book covers three generations (I've summarised the first only). It's remarkably hopeful for a nuclear war book, though don't expect hard science.
6. A Tale of Time City - Diana Wynne Jones (1987) - World War II has begun and Vivian is being evacuated. Instead of going to her new family, she's kidnapped by two boys and taken to Time City, which exists outside of time. Something's gone wrong with history, and the boys are sure Vivian has something to do with it. [Time Travel, Young Adult]
This is one of my favourites. It's strange, it's science fiction, it has an android with no fashion sense... what's not to like?
7. Eva - Peter Dickinson (1988) - When Eva is injured in a car accident, her mind is transferred into the body of a chimpanzee. Eva has to adapt to her new life, both in human society and among the captive chimps. [Dystopian, Young Adult]
8. Alien Secrets - Annette Curtis Klause (1993) - Puck has been expelled from school, and boards a space ship to return to her parents. While on board, she helps an alien who's had a treasure stolen. [Space Travel / Mystery, Young Adult]
9. Tria and the Great Star Rescue - Rebecca Kraft Rector (2002) - Tria stays in her pod playing with her holographic best friend. Until her mother sends her an urgent message, telling Tria to enrol in a Back to Basics school. Can Tria survive school and solve the mystery of her mother's disappearance? [Science Fiction, Middle Grade]
10. The City of Ember - Jeanne DuPrau (2003) - The lights are failing in the underground city of Ember. Lina dreams of a city of light, and when she finds a set of instructions, she and her friend Doon set out to find it. [Post-Apocalyptic, Middle Grade]
11. Zahrah the Windseeker - Nnedi Okorafor-Mbachu / Nnedi Okorafor (2005) - Zahrah is dada--she has vines growing in her hair. When her best friend's life is threatened, her only chance to save him includes facing the things that make her different. [Science Fantasy, Young Adult]
Some elements come across as fantasy (like the dadalocks). Others science fictional (the plant technology). So for me, this is a science fantasy.
12. Life as We Knew It - Susan Beth Pfeffer (2006) - When a meteor knocks the moon closer to Earth, the world is devastated by tsunamis and earthquakes. Miranda and her family struggle to survive as their world falls apart around them. [Apocalyptic, Young Adult]
13. The Adoration of Jenna Fox - Mary E. Pearson (2008) - A girl wakes up from a coma and is told she's Jenna Fox, but why can she remember so little of her life before? [Near Future, Young Adult]
14. Across the Universe - Beth Revis (2011) - Amy is frozen and placed on a colony ship. She expects to be woken when they reach their destination, but something goes wrong and she's woken early. [Space Travel, Young Adult]
I'll admit, I didn't get past the first couple of chapters... but I'm about as romantic as a brick. So it may appeal more to others.
15. Tankborn - Karen Sandler (2011) - Kayla and Mishalla were grown in a tank, and therefore work as slaves in their society. When the children Mishalla is caring for start disappearing, the girls work together to uncover what's happening to them. [Dystopian, Young Adult]
Feel free to mention other titles in the comments, discuss what you thought of the listed books, etc. The main thing is I'm trying to keep this as books for children and teenagers (as opposed to adults), science fiction rather than fantasy (though science fantasy is fine), with female protagonists (or characters who don't fit neatly into a boy/girl divide... mainly, I'm avoiding boys, as no one has issues naming science fiction books with male leads).