diff --git a/x-pack/plugins/security_solution/public/hosts/components/hosts_table/columns.tsx b/x-pack/plugins/security_solution/public/hosts/components/hosts_table/columns.tsx
index d6c51b2bfe05e9..a95f3433741e08 100644
--- a/x-pack/plugins/security_solution/public/hosts/components/hosts_table/columns.tsx
+++ b/x-pack/plugins/security_solution/public/hosts/components/hosts_table/columns.tsx
@@ -90,7 +90,13 @@ export const getHostsColumns = (): HostsTableColumns => [
   },
   {
     field: 'node.host.os.name',
-    name: i18n.OS,
+    name: (
+      <EuiToolTip content={i18n.OS_LAST_SEEN_TOOLTIP}>
+        <>
+          {i18n.OS} <EuiIcon color="subdued" type="iInCircle" className="eui-alignTop" />
+        </>
+      </EuiToolTip>
+    ),
     truncateText: false,
     hideForMobile: false,
     sortable: false,
diff --git a/x-pack/plugins/security_solution/public/hosts/components/hosts_table/translations.ts b/x-pack/plugins/security_solution/public/hosts/components/hosts_table/translations.ts
index 773a052dc71d0a..0354d7a2af71d3 100644
--- a/x-pack/plugins/security_solution/public/hosts/components/hosts_table/translations.ts
+++ b/x-pack/plugins/security_solution/public/hosts/components/hosts_table/translations.ts
@@ -32,6 +32,21 @@ export const FIRST_LAST_SEEN_TOOLTIP = i18n.translate(
   }
 );
 
+export const HOST_RISK_TOOLTIP = i18n.translate(
+  'xpack.securitySolution.hostsTable.hostRiskToolTip',
+  {
+    defaultMessage:
+      'Host risk classifcation is determined by host risk score. Hosts classified as Critical or High are indicated as risky.',
+  }
+);
+
+export const OS_LAST_SEEN_TOOLTIP = i18n.translate(
+  'xpack.securitySolution.hostsTable.osLastSeenToolTip',
+  {
+    defaultMessage: 'Most recently observed OS',
+  }
+);
+
 export const OS = i18n.translate('xpack.securitySolution.hostsTable.osTitle', {
   defaultMessage: 'Operating system',
 });