Ghost does ×1 to Steel

Generations VI to IX, single types. The other way round, Steel against Ghost, is ×1.

65 Ghost and 65 Steel species among the 1025 this site covers.

Attacker, Fire and Ghost Blacephalon sprite

damage×1Generations VI to IX

Defender, Rock and Steel Stakataka sprite

Ghost against Steel has changed: ×½ in Generations II to V, then ×1 in Generations VI to IX.

Steel did not exist in Generation I, so Ghost against Steel has no value there.

Strongest Ghost attackers

Blacephalon leads Ghost at Sp. Atk 151

Sturdiest Steel defenders

Dual types that change the answer