Objective: To explore: (1) how haematological cancer survivors and their support persons perceive the overall performance of the support person; (2) disagreement between survivor and support person ratings; and (3) characteristics associated with support persons rating their performance poorly. Methods: This is a substudy of a larger project of Australian haematological cancer survivors and their support persons. For this substudy, haematological cancer survivors were recruited from 4 Australian population‐based cancer registries and asked to pass on a questionnaire package to their support persons. Survivors who passed on a questionnaire package to their support person were asked to answer questions about the support person and how they perceived the support person's performance. Similarly, support persons answered questions on their own performance as a support person. Results: A total of 924 haematological cancer survivors and 821 support persons were eligible for this study. Most survivors rated their support person as performing very well (84%) while less than half (48%) of support persons rated their own performance as very well. There was significant disagreement between survivor and their support person (dyad) ratings of the support person's performance. Support persons with above normal levels of depression (vs those with normal levels) had significantly higher odds of rating their own performance as “not well/somewhat well.” Conclusions: Health care providers should consider providing additional education and skills‐based interventions to support persons who experience increased symptoms of depression.