diff --git a/README.md b/README.md
index 6a3dbf5..9cbe0e6 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,9 @@ NOTE: There is no PWD hook provided for POSIX shells.
 
 ### Environment variables
 
-- `$_ZO_ECHO`: `z` will print the matched directory before navigating to it
 - `$_ZO_DATA`: sets the location of the database (default: `~/.zo`)
+- `$_ZO_ECHO`: `z` will print the matched directory before navigating to it
+- `$_ZO_EXCLUDE_DIRS`: list of directories separated by platform-specific
+    characters (`:` on Linux and macOS, and `;` on Windows) to be excluded from
+    the database
 - `$_ZO_MAXAGE`: sets the maximum total rank after which entries start getting deleted