- Simoni
- Simonneau
- Simons
- Simpson
- Simpson Cormier
- Sinclair
- Singleton
- Sinnott
- Sipello
- Sippley
- Siritsky
- Sirois
- Sisk
- Sit
- Sivret
- Sizer
- Sjewezyk
- Sjogren
- Skane
- Skarkupka
- Skelton
- Skeoch
- Skerry
- Skillings
- Sklasko
- Skog
- Skowfoe
- Skur
- Skutle
- Skworchinski
- Skyrie
- Slack
- Slater
- Slay
- Sleep
- Sleeper
- Sliffe
- Slipp
- Slocum
- Smail
- Small
- Smart
- Smiley
- Smith
- Smithers
- Smithers-Leger
- Smyth
- Smythe
- Snay
- Sneider
- Snell
- Snider
- Snow
- Snyder
- Sobey
- Soctomah
- Sodtz
- Soini
- Sojka
- Solimeno
- Solkonski
- Solla
- Solomon
- Solomone
- Solvang
- Soly
- Somers
- Somersville
- Somerville
- Sommerfield
- Sommerville
- Sonier