Kassidy is the K-spelling of Cassidy, an Irish surname turned first name that crossed over into widespread American use in the 1990s. It peaked in 2000 at the height of the K-spelling wave and carries both the rugged charm of its outlaw associations and the softness that made Cassidy a unisex phenomenon.
Irish Origins and the Cassidy Surname
Cassidy derives from the Irish Ó Caiside, a Gaelic surname meaning descendant of Caiside, where Caiside itself likely relates to the Irish word for love or twisted/curly. As a given name, Cassidy gained traction in the United States partly through the TV Western Hopalong Cassidy and later through the Grateful Dead's song of the same name, both lending the name a freewheeling, American frontier energy. The K-spelling variant Kassidy emerged as parents in the 1990s favored K-initial spellings: Kayla, Kaitlyn, Kristin, giving familiar names a slightly more distinctive look. Among Irish-origin names, Kassidy shares the category with Keira, Kinslee, and Brynn.
The Unisex Range
Cassidy and its variants have been used for both boys and girls, though the name skews strongly female in recent decades. The K-spelling seems to lean even more feminine in practice, as it visually aligns with Kylie, Kyla, and Kelsey rather than the more neutral Cassidy. With 21,037 total SSA records, Kassidy has substantial usage, more than enough to feel grounded, while sitting outside the current top 500. Siblings named Kassidy often pair well with names like Harlee, Kiera, or Brylee for a consistent Irish-American aesthetic.
Counter-Reading: The Spelling Weight
Every Kassidy will spend time correcting people who write Cassidy. That's not a dealbreaker, but it's a real-world tax. The K-spelling doesn't change pronunciation, so any distinctiveness is visual rather than sonic. If the original Irish surname spelling is important, Cassidy gets the point across with less friction. See 2000s names for the era that made this spelling peak.