AbstractWith rapid development of space engineering, research on life sciences in space is being conducted extensively, especially cellular and molecular studies on space medicine. Stem cells, undifferentiated cells that can differentiate into specialized cells, are considered a key resource for regenerative medicine. Research on stem cells under conditions of microgravity during a space flight or a ground‐based simulation has generated several excellent findings. To help readers understand the effects of outer space and ground‐based simulation conditions on stem cells, we reviewed recent studies on the effects of microgravity (as an obvious environmental factor in space) on morphology, proliferation, migration, and differentiation of stem cells.