diff --git a/theme/boost/scss/moodle/icons.scss b/theme/boost/scss/moodle/icons.scss
index fa6baf1999c..66b9456ea46 100644
--- a/theme/boost/scss/moodle/icons.scss
+++ b/theme/boost/scss/moodle/icons.scss
@@ -137,6 +137,7 @@ $iconsizes: map-merge((
     .activityicon,
     .icon {
         margin: 0;
+        font-size: 24px;
         height: 24px;
         width: 24px;
     }
diff --git a/theme/boost/style/moodle.css b/theme/boost/style/moodle.css
index f0ed1ec8910..d86810e98e6 100644
--- a/theme/boost/style/moodle.css
+++ b/theme/boost/style/moodle.css
@@ -15896,6 +15896,7 @@ blockquote {
 .activityiconcontainer .activityicon,
 .activityiconcontainer .icon {
   margin: 0;
+  font-size: 24px;
   height: 24px;
   width: 24px;
 }
diff --git a/theme/classic/style/moodle.css b/theme/classic/style/moodle.css
index e56a603af83..46086ea060a 100644
--- a/theme/classic/style/moodle.css
+++ b/theme/classic/style/moodle.css
@@ -15896,6 +15896,7 @@ blockquote {
 .activityiconcontainer .activityicon,
 .activityiconcontainer .icon {
   margin: 0;
+  font-size: 24px;
   height: 24px;
   width: 24px;
 }