diff --git a/theme/boost/lang/en/theme_boost.php b/theme/boost/lang/en/theme_boost.php
index 97e698385bd..a5435058658 100644
--- a/theme/boost/lang/en/theme_boost.php
+++ b/theme/boost/lang/en/theme_boost.php
@@ -34,8 +34,6 @@ $string['bootswatch_desc'] = 'A bootswatch is a set of Bootstrap variables and c
 $string['choosereadme'] = 'Boost is a modern highly-customisable theme. This theme is intended to be used directly, or as a parent theme when creating new themes utilising Bootstrap 4.';
 $string['currentinparentheses'] = '(current)';
 $string['configtitle'] = 'Boost';
-$string['fontsize'] = 'Theme base fontsize';
-$string['fontsize_desc'] = 'Enter a fontsize in %';
 $string['generalsettings'] = 'General settings';
 $string['nobootswatch'] = 'None';
 $string['pluginname'] = 'Boost';
diff --git a/theme/boost/lib.php b/theme/boost/lib.php
index 68a20f85a8c..5a7ac95064c 100644
--- a/theme/boost/lib.php
+++ b/theme/boost/lib.php
@@ -150,9 +150,5 @@ function theme_boost_get_pre_scss($theme) {
         $scss .= $theme->settings->scsspre;
     }
 
-    if (!empty($theme->settings->fontsize)) {
-        $scss .= '$font-size-base: ' . (1 / 100 * $theme->settings->fontsize) . "rem !default;\n";
-    }
-
     return $scss;
 }