ObjectiveTo determine the acceptability, internal consistency and test–retest reliability of self-efficacy, motivation and knowledge scales relating to pre-school children’s nutrition, oral health and physical activity.DesignAn online questionnaire was completed twice with an interval of 7–11d.SettingOnline questionnaires were sent to participants via email from nursery managers. The parent questionnaire was also available on the parenting website www.netmums.com.ParticipantsEighty-two parents and sixty-nine nursery staff from Bristol, UK who had and worked with 2–4-year-olds, respectively.ResultsResponse rates were 86·3 and 86·0 % and missing data 15·9 and 14·5 % for the second administration of the parent and nursery staff questionnaires, respectively. Weighted κ coefficients for individual items mostly fell under the ‘moderate’ agreement category for the parental (75·0 %) and nursery staff (55·8 %) items. All self-efficacy and motivation scales had acceptable levels of internal consistency (Cronbach’s α coefficients>0·7). The intraclass correlation coefficients for the self-efficacy, motivation and knowledge scales ranged between 0·48 and 0·82. Paired t tests found an increase between test and retest knowledge scores for the Nutrition Motivation (t=−2·91, df=81, P=0·00) and Knowledge (t=−3·22, df=81, P=0·00) scales in the parent questionnaire.ConclusionsOur findings demonstrate that the items and scales show good acceptability, internal consistency and test–retest reliability.