A chronological list of boys that Lisa has shown romantic interest in:

Confirmed[]

1. S04E15/S09E17: Ralph Wiggum ("I Love Lisa", non-canonical "Lisa the Simpson")
2. S06E19: Hugh Parkfield ("Wedding")
3. S08E07/S19E12/VABF02: Nelson Muntz ("Lisa's Date with Density", non-canonical "Love, Springfieldian Style" and "Barthood")
4. S12E04: Jesse Grass ("Lisa the Tree Hugger")
5. S12E18: Thelonious ("Trilogy of Error")
6. S14E18: Luke Stetson ("Dude, Where's My Ranch?")
7. S14E12 and others: Milhouse Van Houten (non-canonical "I'm Spelling as Fast as I Can" and others)
8. The Simpsons Movie: Colin (The Simpsons Movie)
9. S21E12: Milhoose ("Boy Meets Curl")
10. S22E04: Edmund ("Treehouse of Horror XXI")
11. S23E13: Nick ("The Daughter Also Rises")
12. S25E17: Lucas Bortner ("Luca$")
13. S27E17: Jack Deforest ("The Burns Cage")
14. S28E12: Blake Black ("The Great Phatsby")
15. S29E10: Brendan ("Haw-Haw Land")
16. Simpsons Comics #33: Martin Prince (Rhymes and Misdemeanors)
17. Simpsons Comics #97: Q-Bert Spuckler (Feud, Glorious Feud!)