diff --git a/changelogs/fragments/6964.yml b/changelogs/fragments/6964.yml
new file mode 100644
index 000000000000..b028225e2800
--- /dev/null
+++ b/changelogs/fragments/6964.yml
@@ -0,0 +1,2 @@
+fix:
+- Update z-index of sidecar container to make it more than mask, from 1000 to 1001. ([#6964](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/6964))
\ No newline at end of file
diff --git a/src/core/public/overlays/sidecar/components/sidecar.scss b/src/core/public/overlays/sidecar/components/sidecar.scss
index 1878b92b5074..7041abe74fd3 100644
--- a/src/core/public/overlays/sidecar/components/sidecar.scss
+++ b/src/core/public/overlays/sidecar/components/sidecar.scss
@@ -6,7 +6,9 @@
 .osdSidecarFlyout {
   box-shadow: initial;
   position: fixed;
-  z-index: 1000;
+
+  // Sidecar z-index should more than mask. Actually will be 1001.
+  z-index: $euiZMaskBelowHeader + 1;
   background: lightOrDarkTheme($euiColorGhost, $euiColorInk);
   display: flex;