diff --git a/desktop/.gitignore b/desktop/.gitignore
new file mode 100644
index 0000000..63cf7d3
--- /dev/null
+++ b/desktop/.gitignore
@@ -0,0 +1,18 @@
+
+# Object files (assembler output, pre-linking)
+*.o
+
+# Rebuilt segments (temporary)
+*.built
+
+# Listing files (to review offsets)
+*.list
+
+# Output files (ProDOS file type F1)
+*.F1
+
+# Directory mounted in Virtual ][ as a ProDOS volume
+mount
+
+# OS-specific files
+.DS_Store