Green REITs have become a hot topic in recent years. There have been plenty of studies on the asset growth anomaly and Green REITs' performance, yet little about the asset growth effect among Green REITs. To fill in this gap, this research adopted the portfolio sort test and Fama-Macbeth regressions and found out that although the asset growth effect seems to exist and has a different presentation from other equities, the observed anomaly is likely attributed to the difference in greenness rather than the asset growth itself. This research concluded that the asset growth effect is not statistically significant in the field of Green REITs.