In 2019, local healthcare systems in England were asked to develop formal plans to reduce health inequalities. Here, we explore plans to understand how local healthcare systems conceptualise health inequalities and why. A broad Internet search and targeted search of NHS websites were conducted to identify all publicly accessible healthcare planning documents (National Health Service (NHS) Long-Term Plan (LTP) response documents) produced by local health partnerships in England. A thematic document analysis of the accessible plans was undertaken in NVivo by coding text relating to health inequalities. Of the 44 documents developed, 13 were publicly accessible. These 13 local plans were submitted to NHS England for review between September 2019 and January 2020 and averaged 167 pages (range: 41-273 pages). Only one document contained a chapter dedicated to health inequalities. After analysis, five themes were identified: (1) variation and (2) vagueness explained how health inequalities were conceptualised and (3) use of value judgements, (4) lack of prior conceptualisation and approach and (5) a lack of commitment to action in the documents to reduce health inequalities explained what led to the overall vagueness and variation. Local healthcare systems were found to conceptualise health inequalities in a vague and varying manner, and their conceptualisations did not reflect established health inequalities frameworks. A clear conceptual national framework for addressing health inequalities is needed to support local healthcare systems, so they can address health inequalities meaningfully and sustainably.