Tishri 22, the day after the seventh day of Sukkot, is the holiday Shemini Atzeret. In Israel, Shemini Atzeret is also the holiday of Simchat Torah. Outside of Israel, where extra days of holidays are held, only the second day of Shemini Atzeret is Simchat Torah: Shemini Atzeret is Tishri 22 and 23, while Simchat Torah is Tishri 23.
These two holidays are commonly thought of as part of Sukkot, but that is technically incorrect; Shemini Atzeret is a holiday in its own right and does not involve some of the special observances of Sukkot. We do not take up the lulav and etrog on these days, and our dwelling in the sukkah is more limited, and performed without reciting a blessing.