diff --git a/src/components/Grid.tsx b/src/components/Grid.tsx
index 81092970..c8b467b0 100644
--- a/src/components/Grid.tsx
+++ b/src/components/Grid.tsx
@@ -153,7 +153,7 @@ export const Grid = ({
 
     const skipHeader = sizeColumns === "auto-skip-headers" && !isEmpty(params.rowData);
     if (sizeColumns === "auto" || skipHeader) {
-      const result = autoSizeColumns({ skipHeader, userSizedColIds: userSizedColIds.current });
+      const result = autoSizeColumns({ skipHeader, userSizedColIds: userSizedColIds.current, includeFlex: true });
       if (isEmpty(params.rowData)) {
         if (!hasSetContentSizeEmpty.current && result && !hasSetContentSize.current) {
           hasSetContentSizeEmpty.current = true;
diff --git a/src/contexts/GridContext.tsx b/src/contexts/GridContext.tsx
index 77635e0b..b11ccfaa 100644
--- a/src/contexts/GridContext.tsx
+++ b/src/contexts/GridContext.tsx
@@ -10,6 +10,7 @@ export interface AutoSizeColumnsProps {
   skipHeader?: boolean;
   colIds?: Set<string> | string[];
   userSizedColIds?: Set<string>;
+  includeFlex?: boolean;
 }
 
 export type AutoSizeColumnsResult = { width: number } | null;
diff --git a/src/contexts/GridContextProvider.tsx b/src/contexts/GridContextProvider.tsx
index bbb4609e..d060e03b 100644
--- a/src/contexts/GridContextProvider.tsx
+++ b/src/contexts/GridContextProvider.tsx
@@ -394,12 +394,16 @@ export const GridContextProvider = <RowType extends GridBaseRow>(props: PropsWit
    * Resize columns to fit container
    */
   const autoSizeColumns = useCallback(
-    ({ skipHeader, colIds, userSizedColIds }: AutoSizeColumnsProps = {}): AutoSizeColumnsResult => {
+    ({ skipHeader, colIds, userSizedColIds, includeFlex }: AutoSizeColumnsProps = {}): AutoSizeColumnsResult => {
       if (!columnApi) return null;
       const colIdsSet = colIds instanceof Set ? colIds : new Set(colIds);
       const colsToResize = columnApi.getColumnState().filter((colState) => {
         const colId = colState.colId;
-        return (isEmpty(colIdsSet) || colIdsSet.has(colId)) && !userSizedColIds?.has(colId) && !colState.flex;
+        return (
+          (isEmpty(colIdsSet) || colIdsSet.has(colId)) &&
+          !userSizedColIds?.has(colId) &&
+          (includeFlex || !colState.flex)
+        );
       });
       if (!isEmpty(colsToResize)) {
         columnApi.autoSizeColumns(