The meridian 78° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole. The 78th meridian east forms a great circle with the 102nd meridian west.

From Pole to Pole

Starting at the North Pole and heading south to the South Pole, the 78th meridian east passes through: ! scope="col" width="120" | Co-ordinates ! scope="col" | Country, territory or sea ! scope="col" | Notes ! scope="row" style="background:#b0e0e6;" | Arctic Ocean ! scope="row" style="background:#b0e0e6;" | Kara Sea ! scope="row" | 🇷🇺 ! scope="row" style="background:#b0e0e6;" | Yuratski Bay ! scope="row" | 🇷🇺 ! scope="row" style="background:#b0e0e6;" | Khalmyer Bay ! scope="row" | 🇷🇺 ! scope="row" style="background:#b0e0e6;" | Taz Estuary ! scope="row" | 🇷🇺 ! scope="row" style="background:#b0e0e6;" | Taz Estuary ! scope="row" | 🇷🇺 ! scope="row" | 🇰🇿 East Kazakhstan Region Almaty Region passing through Lake Balkhash ! scope="row" | 🇰🇬 ! scope="row" | ! scope="row" | Aksai Chin ! scope="row" | 🇮🇳 ! scope="row" style="background:#b0e0e6;" | Indian Ocean ! scope="row" style="background:#b0e0e6;" | Southern Ocean ! scope="row" | Antarctica