In the current context where competition in the project consulting sector has increased, it is essential to apply models that allow to increase the effectiveness of the company to successfully meet the needs of customers. This research deals with the design and implementation of a Management Model based on Lean Service within a consulting firm with the objective of eliminating those wastes or mudas that can be identified in the processes or core within the organization. For this, the Lean Service methodology will be developed, which consists of 2 phases where the first one consists of a preliminary phase and the second one is the implementation phase. The first phase consists of getting the permission of the top management, the formation of the lean team, the assessment of the Lean work and the design of the Lean plan. The second phase, which is the implementation, consists of the application of the Lean Service methodology where tools such as Value Stream Mapping are used to identify the cycle time given the set of activities that are performed within the operational processes Value Proposition and Service Delivery. Likewise, tools such as 5S, Suggestion Systems, Standardized Work and Visual Service Management will be applied. With the implementation of the Lean Service methodology, costs and time will be reduced in the two operative processes: Value Proposition Process and Service Provision Process.