WP Widget Disable

Disable sidebar and dashboard widgets with an easy-to-use interface.

This simple plugin allows you to disable any sidebar and dashboard widget for the current WordPress site you are on. It provides a simple user interface available to users with edit_theme_options capabilities (usually Administrator role) available under Appearance -> Disable Widgets. After saving the settings, the sidebar and dashboard widgets are removed from and the user can’t see those widgets anymore.

Check it out on WordPress.org