Internet use provides cognitive stimulation and thereby may contribute to the accumulation of cognitive reserve that is proposed to be instrumental for maintaining cognitive health in ageing. As the first study so far, we examined possible gender differences in the relationship between Internet use and subsequent cognitive decline over six years assessed through changes in Trail Making Test (TMT) accomplishment time in 897 older adults. Latent change score modelling (taking into account baseline cognitive level, chronic diseases, age, and central contributions to cognitive reserve through education, profession, and leisure engagement) revealed a significant interaction of frequency of Internet use and gender. More frequent Internet use in the first wave of data collection significantly predicted a smaller subsequent augmentation in TMT accomplishment time (i.e., a smaller subsequent cognitive decline) only in men, but not in women. In conclusion, frequent Internet use may contribute to the accumulation of cognitive reserve. The gender difference noted highlights an advantage for males. While this finding could be interpreted as gender-specific, it may be that the Internet activities males engage in differ from those of females, calling for a fine-grained investigation of Internet-based activities in future studies