An endoscope tool coupling that facilitates the placement and positioning of a surgical tool within an endoscope. The tool coupling may be configured to accommodate differences in lengths between the surgical tool and the endoscope, which may allow a user to precisely position and maintain the distal end of a surgical tool in a desired location relative to the distal end of the endoscope despite differences and variations in lengths. The tool coupling may have an adjustable configuration to accommodate variations in tool and/or endoscope lengths. The tool coupling employ an arrangement that allows a user to easily increase or decrease the length of the coupling, such as by using a telescoping arrangement. A locking arrangement or mechanism may be provided to secure the coupling in a selected configuration for maintaining the surgical tool in a desired location relative to the endoscope. The tool coupling may be configured to generate a preload on the surgical tool when the tool is positioned in a desired location relative to the endoscope. The tool coupling may be configured to allow for the withdrawal and reintroduction of the same or a similar surgical tool without changing or impacting the original length adjustment and/or preload for the particular tool/endoscope arrangement. The tool coupling may be configured as a separate device that can be attached to various endoscopes, or the tool coupling may be an integrated component of the endoscope.