Purpose: This research paper seeks to determine the relationship between internal and external customer satisfaction in order to activate the marketing of tourism services for Algerian small and medium enterprises by practicing internal marketing. Methodology: In order to answer the raised questions and test the validity of the hypotheses, and after reviewing previous studies, the descriptive analytical approach was relied upon, as this approach is one of the forms of scientific description and interpretation organized to describe the variable under study, depict it quantitatively, and analyze it. To extract the results, one of the methods of this approach was relied upon, which is the field survey by investigating the opinions of employees of the Algerian small and medium tourism enterprises under study on the impact of internal marketing on achieving internal and external customer satisfaction; to obtain data and information that help in coming up with results to provide suggestions and recommendations. The researchers used the questionnaire in this. The study community was selected, which was all small and medium tourism enterprises (agencies, hotels, airports, ...) operating in the Algerian tourism sector. Based on the study community, a random sample of 20 tourism enterprises operating in various parts of the country was selected. The sampling unit (items) was represented by the employees of the institutions under study. 140 questionnaires were distributed, 126 of which were returned, thus the return rate was 90%. Therefore, the study sample is 20 small and medium enterprises represented by 126 individuals. Results: The study concluded that there is a role for internal marketing procedures in achieving internal customer satisfaction, and that there is a role for internal customer satisfaction in achieving external customer satisfaction.. Practical Implications: The practical implications of the research were to recommend the need to expand the interest of Algerian small and medium enterprises in internal marketing, due to its major role in improving the organizational climate and achieving both job satisfaction and external customer satisfaction. Originality/Value: This study contributes to the growing body of knowledge on the concept of internal marketing application in SMEs as a necessity to achieve internal and external customer satisfaction, and can contribute something new to both practitioners as the study provides actionable insights for developing policies for these organizations.