diff --git a/.changeset/short-falcons-march.md b/.changeset/short-falcons-march.md
new file mode 100644
index 0000000000..7742891fcf
--- /dev/null
+++ b/.changeset/short-falcons-march.md
@@ -0,0 +1,5 @@
+---
+'@primer/css': patch
+---
+
+Add default font weight (--base-text-weight-normal, 400) to body
diff --git a/src/base/base.scss b/src/base/base.scss
index 8d748ad404..39b6e6b8f8 100644
--- a/src/base/base.scss
+++ b/src/base/base.scss
@@ -15,6 +15,7 @@ button {
 body {
   font-family: $body-font;
   font-size: var(--body-font-size, $body-font-size);
+  font-weight: var(--base-text-weight-normal, 400);
   line-height: $body-line-height;
   color: var(--fgColor-default, var(--color-fg-default));
   background-color: var(--bgColor-default, var(--color-canvas-default));