diff --git a/docs/G-Codes.md b/docs/G-Codes.md
index 27349f9d..38ae2ca3 100644
--- a/docs/G-Codes.md
+++ b/docs/G-Codes.md
@@ -19,8 +19,12 @@ Klipper supports the following standard G-Code commands:
 - Get extruder temperature: `M105`
 - Set extruder temperature: `M104 [T<index>] [S<temperature>]`
 - Set extruder temperature and wait: `M109 [T<index>] S<temperature>`
+  - Note: M109 always waits for temperature to settle at requested
+    value
 - Set bed temperature: `M140 [S<temperature>]`
 - Set bed temperature and wait: `M190 S<temperature>`
+  - Note: M190 always waits for temperature to settle at requested
+    value
 - Set fan speed: `M106 S<value>`
 - Turn fan off: `M107`
 - Emergency stop: `M112`