Task-unrelated thought (TUT) occurs frequently in our daily lives and across a range of tasks, but we know little about how this phenomenon arises during and influences the way we communicate. Conversations also provide a novel opportunity to assess the alignment (or divergence) in TUT during dyadic interactions. We conducted a study to determine: (a) the frequency of TUT during conversation as well as how partners align/diverge in their rates of TUT, (b) the subjective and behavioral correlates of TUT and TUT divergence during conversation, and (c) if perceived social group identity impacts TUT and TUT divergence during conversation. We used a minimal groups induction procedure to assign participants (N = 126) to either an "ingroup," "outgroup," or "control" condition. We then asked them to converse with one another via a computer-mediated text chat application for 10 min while self-reporting TUTs. On average, participants reported TUT about once every 2 min; however, this rate was lower for participants in the "ingroup" condition, compared to the "control" condition. Conversational pairs in the "ingroup" condition were also "aligned" more in their rates of TUT compared to the "outgroup condition." Finally, we discuss subjective and behavioral correlates of TUT and TUT divergence in conversations, such as valence, turn-taking ratios, and topic shifts.