diff --git a/docs/index.rst b/docs/index.rst
index 96b0b92be8f5..54ca853e5539 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -6,6 +6,7 @@
 .. image:: ./logo/LightGBM_logo_black_text.svg
    :align: center
    :width: 600
+   :alt: Light Gradient Boosting Machine logo.
 
 |