diff --git a/README.md b/README.md
index c7e64dbaa..9e57a074f 100644
--- a/README.md
+++ b/README.md
@@ -66,7 +66,7 @@ Once installed, run `fish` from your current shell to try fish out!
 Running fish requires:
 
 * curses or ncurses (preinstalled on most \*nix systems)
-* some common \*nix system utilities (currently `mktemp` and `seq`), in addition to the basic posix utilities
+* some common \*nix system utilities (currently `mktemp` and `seq`), in addition to the basic POSIX utilities
 * gettext (library and `gettext` command), if compiled with translation support
 
 The following optional features also have specific requirements: