Mental time travel is the ability to mentally project oneself backward in time to relive past experiences and forward in time to pre-live possible future experiences. Previous work has focused on MTT in its voluntary form. Here, we introduce the notion of involuntary MTT. We examined involuntary versus voluntary and past versus future MTT in a diary study. We found that involuntary future event representations—defined as representations of possible personal future events that come to mind with no preceding search attempts—were (...) as common as involuntary autobiographical memories and similar to them regarding cuing and subjective qualities. Future MTT involved more positive and idyllic representations than past MTT. MTT into the distant future/past involved more representations of cultural life script events than MTT into the immediate past/future. The findings are discussed in relation to cultural learning and MTT considered as a higher mental process. (shrink)