inSSIDer is a Wi-Fi network scanner application for Microsoft Windows and OS X developed by MetaGeek, LLC.

[4] It has received awards such as a 2008 Infoworld Bossie Award for "Best of Open Source Software in Networking",[5] but as of inSSIDer 3, it is no longer open-source.

inSSIDer began as a replacement for NetStumbler, a popular Windows Wi-Fi scanner, which had not been actively developed for several years and reputedly did not work with modern 64-bit operating systems or versions of Windows higher than Windows XP.

The project was inspired by Charles Putney on The Code Project.