A substantial component of care is provided to stroke survivors by informal caregivers. However, providing such care is often a new and challenging experience and has been linked to a number of adverse outcomes. A range of interventions targeted towards stroke survivors and their family or other informal caregivers have been tested in randomised controlled trials (RCTs). To evaluate the effect of interventions targeted towards informal caregivers of stroke survivors or targeted towards informal caregivers and the care recipient (the stroke survivor). We searched the Cochrane Stroke Group Trials Register (March 2011), CENTRAL (The Cochrane Library Issue 2010, Issue 4), MEDLINE (1950 to August 2010), EMBASE (1980 to December 2010), CINAHL (1982 to August 2010), AMED (1985 to August 2010), PsycINFO (1967 to August 2010) and 11 additional databases. In an effort to identify further published, unpublished and ongoing studies, we searched conference proceedings and trials registers, scanned reference lists of relevant articles and contacted authors and researchers. There were no language restrictions. We included RCTs if they evaluated the effect of non-pharmacological interventions (compared with no care or routine care) on informal caregivers of stroke survivors. We included trials of interventions delivered to stroke survivors and informal caregivers only if the stroke survivor and informal caregiver were randomised as a dyad. We excluded studies which included stroke survivors and caregivers if the stroke survivors were the primary target of the intervention. Two review authors selected studies for inclusion, independently extracted data and assessed methodological quality. We sought original data from trialists. We categorised interventions into three groups: support and information, teaching procedural knowledge/vocational training type interventions, and psycho-educational type interventions. The primary outcome was caregivers' stress or strain. We resolved disagreements by consensus. Eight studies, including a total of 1007 participants, met our inclusion criteria. We did not pool the results of all the studies because of substantial methodological, statistical and clinical heterogeneity. For caregivers' stress or strain we found no significant results within categories of intervention, with the exception of one single-centre study examining the effects of a 'vocational training' type intervention which found a mean difference between the intervention and comparator group at the end of scheduled follow-up of -8.67 (95% confidence interval -11.30 to -6.04, P < 0.001) in favour of the 'teaching procedural knowledge' type intervention group. It was not possible to carry out a meta-analysis of the evidence from RCTs because of methodological, clinical and statistical heterogeneity. One limitation across all studies was the lack of a description of important characteristics that define the informal caregiver population. However, 'vocational educational' type interventions delivered to caregivers prior to the stroke survivor's discharge from hospital appear to be the most promising intervention. However, this is based on the results from one, small, single-centre study.