There are numerous conceptualisations of post-truth in the literature, yet the impact of ‘post-truth’ discourse on political behaviour is neglected. I introduce ‘post-truth’ as a discourse, drawing from the psychoanalytic elements of lack and fantasy along with the fantasmatic logic of explanation, to identify and measure it. In this framework, a ‘post-truth’ discourse embodies lack, fantasy, and emotionality, intertwining to present a fantasmatic logic. I test the truthfulness of ‘post-truth’ discourse in Pakistan in a two-step design. First, I employ a qualitative text analysis to national newspaper articles to detect ‘post-truth’ accounts. Based on this categorization, I design a vignette survey experiment to test the causal relationship between ‘post-truth’ narratives and truthfulness. I surveyed a random sample of 800 respondents from five urban districts in Pakistan. I find that the persuasiveness of post-truth narratives varies across issues but the impact of trust in the source is constant in accepting ‘post-truth’ account as being truthful. Despite overall null results for truthfulness of a ‘post-truth’ account, I highlight how the types of specific discourses, as well as the positive correlation between different types of sentiments (anger and hope) and truthfulness of a ‘post-truth’ account paves the way to further study the interplay between ‘post-truth’ discourse, emotions, and political behaviour.