diff --git a/common/changes/office-ui-fabric-react/issue5857_2018-08-17-18-09.json b/common/changes/office-ui-fabric-react/issue5857_2018-08-17-18-09.json
new file mode 100644
index 0000000000000..ffac4abc13c4b
--- /dev/null
+++ b/common/changes/office-ui-fabric-react/issue5857_2018-08-17-18-09.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "office-ui-fabric-react",
+      "comment": "DetailsList: Account for grouping depth of more than one in width calculation.",
+      "type": "patch"
+    }
+  ],
+  "packageName": "office-ui-fabric-react",
+  "email": "jeffking@gmail.com"
+}
diff --git a/packages/office-ui-fabric-react/src/components/DetailsList/DetailsList.base.tsx b/packages/office-ui-fabric-react/src/components/DetailsList/DetailsList.base.tsx
index 28926110fdeba..6aaaa8ab225b3 100644
--- a/packages/office-ui-fabric-react/src/components/DetailsList/DetailsList.base.tsx
+++ b/packages/office-ui-fabric-react/src/components/DetailsList/DetailsList.base.tsx
@@ -799,10 +799,10 @@ export class DetailsListBase extends BaseComponent<IDetailsListProps, IDetailsLi
     props: IDetailsListProps,
     firstIndex: number
   ): IColumn[] {
-    const { selectionMode, checkboxVisibility, groups } = props;
+    const { selectionMode, checkboxVisibility } = props;
     const rowCheckWidth =
       selectionMode !== SelectionMode.none && checkboxVisibility !== CheckboxVisibility.hidden ? CHECKBOX_WIDTH : 0;
-    const groupExpandWidth = groups ? GROUP_EXPAND_WIDTH : 0;
+    const groupExpandWidth = this._getGroupNestingDepth() * GROUP_EXPAND_WIDTH;
     let totalWidth = 0; // offset because we have one less inner padding.
     const availableWidth = viewportWidth - (rowCheckWidth + groupExpandWidth);
     const adjustedColumns: IColumn[] = newColumns.map((column, i) => {