Observational studies find that family carers of people with dementia who use more emotional support and acceptance-based coping, and less dysfunctional coping, are less depressed and anxious. We hypothesized that interventions effective in reducing psychological symptoms would increase emotional support and acceptance-based coping, or decrease dysfunctional coping. We systematically reviewed randomized controlled trials published up to July 2011, of interventions for carers of people with dementia measuring coping and psychological morbidity. We rated study validity and reported findings. We conducted fixed-effect meta-analyses for interventions where possible. Eight of 433 papers identified by the search met inclusion criteria. All measured coping immediately after intervention. Two interventions significantly decreased depressive or anxiety symptoms: the smaller study found no change in dysfunctional coping. Neither measured emotional support and acceptance-based coping. Meta-analysis found that both group coping skills interventions alone (SMD = -0.39, 95% CI = -0.75 to -0.03, p = 0.04) and with behavioral activation (SMD = -0.26, 95% CI = -0.48 to -0.04, p = 0.02) significantly increased dysfunctional coping, while significantly reducing depressive symptoms. Positive coping (a mix of emotional and solution-focused strategies) increased (SMD = 0.28, 95% CI = 0.05-0.51, p = 0.02) with group coping skills interventions and behavioral activation. Contrary to our hypothesis, dysfunctional coping increased when carer depressive symptoms improved. There was preliminary evidence that emotional support and acceptance-based coping increased, as positive coping increased although solution-focused coping alone did not. More research is needed to elucidate whether successful interventions work through changing coping strategies immediately and in the longer term.