Background: During the past decade, the concept of Lean has spread rapidly within the healthcare sector, but there is a lack of instruments that can measure staff's perceptions of Lean adoption. Thus, the aim of the present study was to develop a questionnaire measuring Lean in healthcare, based on Liker's description of Lean, by adapting an existing instrument developed for the service sector. Methods: A mixed-method design was used. Initially, items from the service sector instrument were categorized according to Liker's 14 principles describing Lean within four domains: philosophy, processes, people and partners and problem-solving. Items were lacking for three of Liker's principles and were therefore developed de novo. Think-aloud interviews were conducted with 12 healthcare staff from different professions to contextualize and examine the face validity of the questionnaire prototype. Thereafter, the adjusted questionnaire's psychometric properties were assessed on the basis of a cross-sectional survey among 386 staff working in primary care. Results: The think-aloud interviews led to adjustments in the questionnaire to better suit a healthcare context, and the number of items was reduced. Confirmatory factor analysis of the adjusted questionnaire showed a generally acceptable correspondence with Liker's description of Lean. Internal consistency, measured using Cronbach's alpha, for the factors in Liker's description of Lean was 0.60 for the factor people and partners, and over 0.70 for the three other factors. Test-retest reliability measured by the intra-class correlation coefficient ranged from 0.77 to 0.88 for the four factors. Conclusions: We designed a questionnaire capturing staff's perceptions of Lean adoption in healthcare on the basis of Liker's description. This Lean in Healthcare Questionnaire (LiHcQ) showed generally acceptable psychometric properties, which supports its usability for measuring Lean adoption in healthcare. We suggest that further research focus on verifying the usability of LiHcQ in other healthcare settings, and on adjusting the instrument if needed.