Tsukuba International School (つくばインターナショナルスクール, TIS) is a private, non-profit school for English-speaking children in Tsukuba, Ibaraki, Japan.

In November 2011, it received authorization to offer the Primary Years Programme (PYP) of the International Baccalaureate (IB).

In June 2014, it received authorization to offer the Middle Years Programme (MYP).

In April 2017, it received authorization to offer the Diploma Programme (DP).

The school is located in the Kamigo region of Tsukuba Science City and the closest stations are Banpaku Kinen Koen on the Tsukuba Express Line and Mitsuma on the Joso Line.