diff --git a/scss/_accordion.scss b/scss/_accordion.scss
index 9b9dc82e83c2..58b8db196174 100644
--- a/scss/_accordion.scss
+++ b/scss/_accordion.scss
@@ -114,6 +114,11 @@ $accordion-icon-transform:                rotate(-180deg) !default;
       border-block-start: 0;
     }
 
+    // Remove bottom border when followed by an open item (to avoid double border)
+    &:has(+ .accordion-item[open]) {
+      border-block-end: 0;
+    }
+
     // Only set a border-radius on the last item if the accordion is collapsed
     &:last-of-type {
       @include border-bottom-radius(var(--accordion-border-radius));
@@ -131,6 +136,11 @@ $accordion-icon-transform:                rotate(-180deg) !default;
     &[open] {
       border-color: var(--theme-border, var(--accordion-border-color));
 
+      // Restore top border for non-first items when open
+      &:not(:first-of-type) {
+        border-block-start: var(--accordion-border-width) solid var(--theme-border, var(--accordion-border-color));
+      }
+
       > .accordion-header {
         color: var(--theme-text, var(--accordion-active-color));
         background-color: var(--theme-bg-subtle, var(--accordion-active-bg));