diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index d8ffe8b..a891380 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -146,6 +146,14 @@
    (RAM) or 1 (non-volatile memory like flash) as test results storage. Default
    value is 0, as writing to the flash significantly slows tests down.
 
+Realm payload specific Build Options
+------------------------------------
+
+-  ``TFTF_MAX_IMAGE_SIZE``: The option needs to be either set by the user or
+   by the platform makefile to specify the maximum size of TFTF binary. This
+   is needed so that the Realm payload binary can be appended to TFTF binary
+   via ``make pack_realm`` build command.
+
 FWU-specific Build Options
 --------------------------