Executive Function (EF) comprises general purpose control processes that regulate thoughts and behaviours. Underlying core skills have been identified, including Shift: the ability to move between mental states, operations, or tasks. Research implicates EF (and Shift specifically) in academic achievement and broader life functioning throughout the life span. Most attempts to develop EF skills directly have focused on memory aspects and/or younger children. Reported benefits are controversial and perhaps limited. This research tackles a particular gap: intervention with adolescent core EF skills, with a focus on Shift, in a typical educational setting.All participant sampling was by convenience. Two experts in EF and three local stakeholders guided intervention development. 22 mainstream Year 8 students (one tutor group) trialled the resulting intervention prototype. A teaching assistant facilitated the implementation, with the form tutor present to occasionally assist.Being an exploratory evaluation, this research used mixed methods with an emphasis on qualitative data. Semi-structured group interviews with experts and a stakeholder focus group were used during the development phase. Standardised baseline and retest data were collected up to three weeks before and four weeks after the implementation phase respectively: a half term's trial during morning form-time. This was complemented by semi-structured feedback interviews with the participating adults and eight students. Transcripts were analysed with Thematic Analysis and the researcher's diary with Content Analysis. The quantitative data were summarised with descriptive statistics and additionally analysed with nonparametric inferential statistics.The study extends available data describing the near benefits of EF intervention. It explores the likely utility of EF intervention both theoretically and from an implementation perspective.