Since 1990, attempts to implement lean, especially by production companies, have grown in number and depth. With the publication of the book Lean Thinking, lean projects quickly spread to other activity sectors, but achieving success in such implementations is not something that can be easily accomplished. Research is in progress to identify why some organizations succeed while others do not; one of the findings points to organizational culture as a crucial factor. This means that before implementing lean in a company, its organizational culture should be analysed, understood and, eventually, modified, to create the necessary openness for the implementation to be successful. This paper aims to explore the relationship between the organizational culture of companies from industry and services and their openness regarding lean implementation. For this, it was developed and applied a two parts questionnaire: one part involves the four traits of the Denison organizational culture survey and the other part the six dimensions of the Cameron and Quinn model (Competing Values Framework). The questionnaire was applied to the top managers of four companies (one from industry, two from services and one with both areas). In terms of organizational culture, the findings revealed that in order to move towards successful lean implementation, some companies need to improve specific traits inherent to Denison’s approach as well as ensure congruence between the dimensions of the Cameron and Quinn model.