diff --git a/.changeset/early-spoons-greet.md b/.changeset/early-spoons-greet.md
new file mode 100644
index 0000000000..c194ce5c8c
--- /dev/null
+++ b/.changeset/early-spoons-greet.md
@@ -0,0 +1,5 @@
+---
+"@primer/css": patch
+---
+
+Always break long `branch-name`s
diff --git a/src/branch-name/branch-name.scss b/src/branch-name/branch-name.scss
index 3209be98a7..600e99b8a9 100644
--- a/src/branch-name/branch-name.scss
+++ b/src/branch-name/branch-name.scss
@@ -8,6 +8,7 @@
   padding: 2px 6px;
   font: 12px $mono-font;
   color: var(--color-fg-muted);
+  word-break: break-all;
   background-color: var(--color-accent-subtle);
   border-radius: $border-radius;