Nelson Muntz Appearences: Most Episodes
While Nelson was "helping" Groundskeeper Willie, Lisa was watching from the window where she laughed at a prank. During detention Lisa was stareing at him and realised that she had a crush on him. Lisa tried to change Nelson's attitude to become more of a gentleman, but she gave up after he lied to her when he threw coleslaw at Principal Skinner's House.

Jesse Grass Appearences: CABF01 - Lisa the Treehugger
Lisa falls for Jesse while he is staging a protest at Krusty Burger. Lisa then joins Jesse's group, Dirt First, where she is asked to prevent loggers from cutting down a tree because Lisa is living in it. When Lightning strikes the tree, Lisa is presumed dead. Jeese cuts off his favourite dread in Lisa's Memory.

Thelonius Appearences: CABF12 - Trilogy of Error
Lisa bumps into Thelonius while rushing to school and it turns out she is in the wrong one. Lisa and Thelonius spin around for hours but Lisa must leave to hand in her science project, Linguo, never to see him again.

Luke Stetson Appearences: EABF13 - Dude, Where's My Ranch?
Lisa meets Luke when she kicked a Rattle Snake egg and he shows her around. When Lisa heard Luke talk to Clara she thought that Luke had a girlfriend. Lisa met Clara on a trail and sent her the wrong way, Bart and Lisa rescue Clara. Clara told Luke about it, Lisa then admits that it was her fault and Luke breaks up with her.

Colin Appearences: The Simpsons Movie
Lisa meets Colin while she is trying to get people to stop dumping, they set up a town meeting, and get the town to stop dumping in the lake. While the town raids the Simpson home, Colin has a bunch of flowers for Lisa which Carl swiftly burns. Colin plays Lisa's song to her, but she has to run away. When Lisa returns to Springfield, Milhouse tells her that Colin is dead but he shows up four seconds later. Lisa and Colin then go off for ice cream.

Hugh Parkfield Appearences: 2F15 - Lisa's Wedding
Initially Hugh and Lisa hate each other, but after needing the same book in the library, they race in reading and end up falling in love. While going back to London for the summer, Lisa comes with him. There, Hugh proposes to Lisa and Lisa accepts. Back in Springfield, The Simpsons, show Hugh the town, Hugh puts up with it, but on their wedding day, he comes clean that he will not allow Homer, Bart and Maggie to see her anymore. Lisa then leaves him.

Milhouse Van Houten Appearences: 2F15 - Lisa's Wedding
When Lisa was 12, Milhouse set the house on fire and rescued Lisa from it, there, she relented on him. At the High School Prom, Lisa and Milhouse went together. For an unknown reason, Lisa leaves Milhouse, but takes advantage of the situation when she's depressed because she's unable to go to Yale. When Bart discovers how Lisa's live will turn out, Bart breaks them up and gives her his scholarship at Yale which he stole from her in the first place.