In a pre-registered cluster randomised controlled trial, 85 lower SES families and their 3- to 4-year old children from 10 different preschools were randomly allocated to take part in The Reader’s Shared Reading programme (intervention) or an existing ‘Story Time’ group at a library (control), once a week for eight weeks. Three outcome measures were assessed at baseline and post-intervention; (i) attendance, (ii) enjoyment of the reading groups, and (iii) caregivers’ knowledge of, attitudes and behaviours towards reading. A fourth, - children’s vocabulary - was assessed at baseline and four weeks post-intervention. Families were significantly more likely to attend the intervention group and rated it more favourably, compared to the control group. However, there were no significant effects on caregivers’ knowledge, attitudes and behaviours, or on children’s language. The intervention was only successful in engaging families from disadvantaged backgrounds in shared reading.