Misionis Bay (Bulgarian: залив Мисионис, ‘Zaliv Misionis’ \'za-liv mi-si-'o-nis\) is the 1.6 km wide bay indenting for 2.35 km the northeast coast of Pickwick Island in the Pitt group of Biscoe Islands, Antarctica. It is entered east of Kusev Point and west of Plakuder Point.
The bay is named after the ancient and medieval town of Misionis in Northeastern Bulgaria.