AIM:The aim of this study was to explore which aspects of their role practice nurses perceive to be most influential and the strategies they employ to promote the MMR vaccine. DESIGN:Qualitative study employing in depth interviews. METHOD:Fifteen London based practice nurses, nine in 2014 and six in 2018, took part in semi-structured interviews that were audio recorded and transcribed verbatim. Qualitative content analysis was used to systematically manage, analyse, and identify themes. RESULTS:Analysis of data identified aspects of their role practice nurses perceived to be most influential (the themes) including: promoting vaccination, assisting parents' to make informed decisions, and provided insight into how they used specific strategies to achieve these in practice. These themes were consistent over both phases of the study. CONCLUSION:The findings provide an understanding of: (i) the practice nurses perceptions of the most important aspects of their role when promoting the measles, mumps, and rubella vaccine; and (ii) the strategies they implemented in practice to achieve these. The latter included assisting parents in their immunization decisions and was facilitated by practice nurses engaging with parents to provide relevant evidence to address parent queries, dispel misconceptions and tailor strategies to promote the measles, mumps, and rubella vaccine. IMPACT:This study addresses the paucity of literature available that specifically explores practice nurses' perceptions of their role concerning the measles, mumps, and rubella vaccine. The findings reveal how practice nurses promote the measles, mumps, and rubella vaccine by identifying strategies to enable parents to make informed decisions. At a time of an increasing incidence of measles, practice nurses have an important public health role in achieving herd immunity levels for measles, mumps, and rubella.