Meaning of SIO
What Does SIO Mean? (Using SIO Online)SIO means "Bye".
Summary of Key Points
Definition for SIOSIO means "Bye". This is the most common definition for SIO on Snapchat, WhatsApp, Facebook, and Twitter. Here is some more information about SIO:
Adults and Teenagers
A Text with SIO
Using SIO on a Cell Phone (SMS Texts, Whatsapp, and Yubl)