Contemporary theories of suicide, such as the Schematic Appraisals Model (SAMS), hypothesize that negative perceptions of social support are implicated in the pathways to suicidal experiences. The SAMS predicts that perceived social support influences suicidal ideation through appraisals of defeat and entrapment. However, such pathways have not been investigated in people who have bipolar disorder. This prospective four-month study tested the influence of perceived social support on later suicidal ideation via changes in defeat, entrapment, and hopelessness, in a sample of eighty euthymic participants with bipolar disorder (N = 62 at follow-up). Linear regression models tested the extent to which perceived social support at baseline predicted changes in suicidal ideation at four months directly and indirectly via changes in defeat, entrapment, and hopelessness. Perceived social support did not directly predict changes in suicidal ideation, but there was a significant indirect mediational pathway between perceived social support at baseline and changes in suicidal ideation over time, via changes in defeat, entrapment and hopelessness, supporting the SAMS. Psychological interventions which target negative perceptions of social support early, in tandem with addressing defeat, entrapment, and hopelessness over time, present a potentially effective approach to counter suicidal ideation in people who experience bipolar disorder.