The purpose of this study is to rethink the impact of transformational leadership on sales employees’ efficiency by elucidating the mediating role of knowledge sharing. This study is applied in purpose and descriptive–correlational in method, adopting a quantitative approach to examine the relationships among transformational leadership, knowledge sharing, and sales employees’ efficiency. The statistical population consisted of sales employees of Shirin Asal Company across various branches in the city of Tabriz. As accurate information regarding the total number of sales employees was not available, the sample size was determined based on methodological considerations for quantitative studies using Cochran’s formula, resulting in a sample of 196 respondents. Convenience sampling was employed, and data from 196 valid questionnaires were collected for analysis. Standardized questionnaires were used to measure the study variables. Transformational leadership was assessed using Rafferty and Griffin’s (2004) questionnaire, comprising 15 items across five dimensions (vision, inspirational communication, intellectual stimulation, supportive leadership, and personal recognition). Sales employees’ efficiency was measured using Hajizadeh’s (2013) standard questionnaire with 16 items across four dimensions (fairness, alignment, work speed, and effective use of equipment and facilities). Knowledge sharing was measured using Khatoun’s (2024) questionnaire with 10 items. Of the 196 distributed questionnaires, 192 were completed and included in the final analysis. The results indicate that transformational leadership has a positive and significant effect on sales employees’ efficiency. In addition, transformational leadership positively and significantly influences knowledge sharing, and knowledge sharing, in turn, has a significant positive effect on sales employees’ efficiency. Path analysis results further reveal that knowledge sharing fully mediates the relationship between transformational leadership and sales employees’ efficiency. By focusing on the sales context, this study contributes to the enrichment of the literature on transformational leadership and knowledge sharing and highlights existing research gaps in understanding the mechanisms through which transformational leadership influences sales employees’ efficiency. The findings provide practical insights for sales managers seeking to enhance employee efficiency through the promotion of transformational leadership and knowledge-sharing practices.