Letter: Y
- yadex - Doom level editor
- yafc - Yet Another FTP/SFTP Client
- yakuake - Terminal emulator for KDE
- yap - High-performance Prolog Compiler
- yasm - Complete rewrite of the NASM assembler
- yaz - Z39.50/SRW/SRU programs
- ytalk - A chat program for multiple users
- yum-utils - Utilities based around the yum package manager
- yumex - Yum Extender graphical package management tool