It is commonly stated that the direction in which we read and write influences our conceptualisation of the flow of time. However, research to date has only established a causal link between reading direction and temporal thought, leaving out the question of whether the act of writing indeed shapes the mental timeline. The current study addresses this gap by examining whether writing direction modulates how events are mapped onto time. Consistent with previous findings, results from a reading experiment showed that participants who read mirror texts (right-to-left orthography) indeed mapped time as flowing leftwards. However, contrary to prevailing assumptions, results from a series of writing experiments showed that participants assigned to a mirror writing condition (right-to-left orthography) displayed the same left-to-right mapping of the flow of time as participants in the standard writing condition (left-to-right orthography), despite progressive increases in mirror-writing training. It is suggested that the act of writing does not shape time concepts because it is not unambiguously unidirectional: the fine-motoric action of forming individual letters is multidirectional and thus interferes with the lateral time–space association obtained with the gross-motoric action of moving the hand/arm sideways.