Brad Konig — A popular boy who stood Harmony up in the tenth grade. Harmony later repays him by turning him into a vampire (cf. "Real Me").

Xander Harris — Harmony, under the influence of a love spell (cf. "Bewitched, Bothered and Bewildered"), relentlessly pursues Xander and berates Cordelia for breaking up with him.

Devon MacLeish (of the band Dingoes Ate My Baby) — According to Oz, "Devon dated her for awhile, but she was too flaky for him, which, stop and marvel at the concept" (cf. "The Harsh Light of Day").

Spike — Harmony and Spike are introduced as an unlikely couple in Season Four of Buffy. Spike is irritated by Harmony's immaturity and treats her as a sexual plaything, although he returns her affection at convenient times. Harmony soon becomes weary of Spike's obsession with killing Buffy and his numerous unfulfilled promises to her. Their highly sexual but rocky relationship continues on and off into Season Five, where they finally break up for good and Harmony moves to Los Angeles. Harmony and Spike are reunited in Angel's fifth and final season, but do not rekindle their relationship (except for a brief, ill-fated fling in the episode "Destiny").

Tobias "Toby" Dupree — Harmony and Toby meet at a bar and strike sparks. However, she awakes the next morning to find him dead, having been bitten by a vampire. Harmony initially fears that she is the killer, but soon discovers the sinister plot of another vampire secretary (cf. "Harm's Way").

Marcus Hamilton — Harmony and Hamilton have a secret relationship, and she deliberately betrays Angel by leaking his secrets to Hamilton, who also allows her to drink his blood.