Introduction: The Integrated Motivational-Volitional model of suicidal behaviour is a predominant theoretical model that contextualises the relationship between perfectionism and suicidal ideation via various potential pathways. Previous research has examined the relationship between socially prescribed perfectionism and social comparisons in the IMV model. However, no research has examined perfectionistic self-presentation in this model, despite research which has found perfectionistic self-presentation to predict unique variance in suicidal ideation. In addition, no research has examined feelings of not mattering as a motivational moderator. Aim: Our study addressed these limitations by examining relationships between socially prescribed perfectionism, perfectionistic self-presentation, negative social comparisons, defeat, entrapment, and suicidal ideation through the lens of the IMV model. Method: Adult participants (N = 520; Mage = 33.09 years, SD = 12.46; 63.6% female) were recruited online via various sources (e.g., mental health charities) and completed an online questionnaire of psychological measures on one occasion. Results: Four mediation models were tested. In the first model, perfectionistic self-presentation mediated the relationship between socially prescribed perfectionism and negative social comparisons. In the second model, negative social comparisons mediated the relationship between perfectionistic self-presentation and defeat. In the third model, defeat mediated the relationship between social comparisons and entrapment. In the fourth model, internal entrapment, but not overall entrapment, mediated the relationship between defeat and suicidal ideation. Conclusion: Findings of the study support central tenants of the IMV model and advocate for the inclusion of perfectionistic self-presentation. In addition, our findings highlight the need to target perfectionistic self-presentational behaviours and negative social comparisons in clinical settings to prevent the development of suicidal ideation.