diff --git a/src/components/Menus/Sidebar/Sidebar.jsx b/src/components/Menus/Sidebar/Sidebar.jsx
index 994b5ed87..d4a31f441 100644
--- a/src/components/Menus/Sidebar/Sidebar.jsx
+++ b/src/components/Menus/Sidebar/Sidebar.jsx
@@ -1,7 +1,7 @@
 import React, { useEffect, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 import classNames from "classnames";
-import { useSelector } from "react-redux";
+import { useDispatch, useSelector } from "react-redux";
 import { useMediaQuery } from "react-responsive";
 
 import FilePanel from "./FilePanel/FilePanel";
@@ -24,9 +24,11 @@ import FileIcon from "../../../utils/FileIcon";
 import DownloadPanel from "./DownloadPanel/DownloadPanel";
 import InstructionsPanel from "./InstructionsPanel/InstructionsPanel";
 import SidebarPanel from "./SidebarPanel";
+import { setSidebarOption } from "../../../redux/EditorSlice";
 
 const Sidebar = ({ options = [], plugins = [], allowMobileView = true }) => {
   const { t } = useTranslation();
+  const dispatch = useDispatch();
   const projectType = useSelector((state) => state.editor.project.project_type);
   const projectImages = useSelector((state) => state.editor.project.image_list);
   const instructionsSteps = useSelector(
@@ -35,6 +37,9 @@ const Sidebar = ({ options = [], plugins = [], allowMobileView = true }) => {
   const instructionsEditable = useSelector(
     (state) => state.editor.instructionsEditable,
   );
+  const selectedSidebarOption = useSelector(
+    (state) => state.editor.selectedSidebarOption,
+  );
   const viewportIsMobile = useMediaQuery({ query: MOBILE_MEDIA_QUERY });
   const isMobile = allowMobileView && viewportIsMobile;
 
@@ -134,28 +139,43 @@ const Sidebar = ({ options = [], plugins = [], allowMobileView = true }) => {
   }
 
   const autoOpenPlugin = plugins?.find((plugin) => plugin.autoOpen);
-
-  const [option, setOption] = useState(
-    autoOpenPlugin
-      ? autoOpenPlugin.name
-      : instructionsEditable || instructionsSteps
-        ? "instructions"
-        : "file",
-  );
-
   const hasInstructions = instructionsSteps && instructionsSteps.length > 0;
+  let defaultOption = "file";
+  if (autoOpenPlugin) {
+    defaultOption = autoOpenPlugin.name;
+  } else if (instructionsEditable || hasInstructions) {
+    defaultOption = "instructions";
+  }
+  const defaultOptionIsAvailable = menuOptions.some(
+    (menuOption) => menuOption.name === defaultOption,
+  );
+  const nextDefaultOption = defaultOptionIsAvailable ? defaultOption : null;
+  const initialOption =
+    selectedSidebarOption === undefined
+      ? nextDefaultOption
+      : selectedSidebarOption;
+  const [option, setOption] = useState(initialOption);
+  const optionIsAvailable =
+    option === null ||
+    menuOptions.some((menuOption) => menuOption.name === option);
 
   useEffect(() => {
-    if (!autoOpenPlugin && (instructionsEditable || hasInstructions)) {
-      setOption("instructions");
+    if (!optionIsAvailable) {
+      setOption(nextDefaultOption);
+      dispatch(setSidebarOption(nextDefaultOption));
     }
-  }, [autoOpenPlugin, instructionsEditable, hasInstructions]);
+  }, [dispatch, nextDefaultOption, optionIsAvailable]);
+
+  const updateOption = (nextOption) => {
+    setOption(nextOption);
+    dispatch(setSidebarOption(nextOption));
+  };
 
   const toggleOption = (newOption) => {
     if (option !== newOption) {
-      setOption(newOption);
+      updateOption(newOption);
     } else if (!isMobile) {
-      setOption(null);
+      updateOption(null);
     }
   };
 
diff --git a/src/components/WebComponentProject/WebComponentProject.test.js b/src/components/WebComponentProject/WebComponentProject.test.js
index 3c7800a58..9d2ed6af3 100644
--- a/src/components/WebComponentProject/WebComponentProject.test.js
+++ b/src/components/WebComponentProject/WebComponentProject.test.js
@@ -1,8 +1,30 @@
 import React from "react";
-import { act, render, screen } from "@testing-library/react";
+import { act, fireEvent, render, screen } from "@testing-library/react";
 import { Provider } from "react-redux";
 import configureStore from "redux-mock-store";
+import {
+  combineReducers,
+  configureStore as configureRealStore,
+} from "@reduxjs/toolkit";
+import { matchMedia, setMedia } from "mock-match-media";
 import WebComponentProject from "./WebComponentProject";
+import { MOBILE_BREAKPOINT } from "../../utils/mediaQueryBreakpoints";
+import EditorReducer, { editorInitialState } from "../../redux/EditorSlice";
+import InstructionsReducer, {
+  instructionsInitialState,
+} from "../../redux/InstructionsSlice";
+import AuthReducer, {
+  authInitialState,
+} from "../../redux/WebComponentAuthSlice";
+
+let mockMediaQuery = (query) => {
+  return matchMedia(query).matches;
+};
+
+jest.mock("react-responsive", () => ({
+  ...jest.requireActual("react-responsive"),
+  useMediaQuery: ({ query }) => mockMediaQuery(query),
+}));
 
 const codeChangedHandler = jest.fn();
 const runStartedHandler = jest.fn();
@@ -23,6 +45,7 @@ let store;
 const renderWebComponentProject = ({
   projectType,
   instructions,
+  imageList = [],
   permitOverride = true,
   loading,
   codeRunTriggered = false,
@@ -38,7 +61,7 @@ const renderWebComponentProject = ({
         components: [
           { name: "main", extension: "py", content: "print('hello')" },
         ],
-        image_list: [],
+        image_list: imageList,
         instructions,
       },
       loading,
@@ -55,7 +78,55 @@ const renderWebComponentProject = ({
   };
   store = mockStore(initialState);
 
-  render(
+  return render(
+    <Provider store={store}>
+      <WebComponentProject {...props} />
+    </Provider>,
+  );
+};
+
+const renderWebComponentProjectWithRealStore = ({
+  projectType,
+  instructions,
+  imageList = [],
+  permitOverride = true,
+  loading,
+  props = {},
+  editorOverrides = {},
+}) => {
+  const rootReducer = combineReducers({
+    editor: EditorReducer,
+    auth: AuthReducer,
+    instructions: InstructionsReducer,
+  });
+  const preloadedState = {
+    editor: {
+      ...editorInitialState,
+      ...editorOverrides,
+      project: {
+        ...editorInitialState.project,
+        project_type: projectType,
+        components: [
+          { name: "main", extension: "py", content: "print('hello')" },
+        ],
+        image_list: imageList,
+        instructions,
+      },
+      loading,
+      openFiles: [],
+      focussedFileIndices: [],
+    },
+    instructions: {
+      ...instructionsInitialState,
+      currentStepPosition: 3,
+      permitOverride,
+    },
+    auth: authInitialState,
+  };
+
+  store = configureRealStore({ reducer: rootReducer, preloadedState });
+
+  return render(
     <Provider store={store}>
       <WebComponentProject {...props} />
     </Provider>,
@@ -254,6 +325,9 @@ describe("When code run finishes", () => {
 
 describe("When withSidebar is true", () => {
   beforeEach(() => {
+    setMedia({
+      width: "1000px",
+    });
     renderWebComponentProject({
       props: { withSidebar: true, sidebarOptions: ["settings"] },
     });
@@ -268,6 +342,71 @@ describe("When withSidebar is true", () => {
   });
 });
 
+describe("When resizing across the mobile breakpoint", () => {
+  test("Keeps the selected sidebar panel after switching to mobile and back", () => {
+    setMedia({
+      width: "1000px",
+    });
+
+    const view = renderWebComponentProjectWithRealStore({
+      imageList: [{ filename: "earth.png", url: "/earth.png" }],
+      props: { withSidebar: true, sidebarOptions: ["file", "images"] },
+    });
+
+    fireEvent.click(screen.getByTitle("sidebar.images"));
+    expect(screen.queryByText("imagePanel.gallery")).toBeInTheDocument();
+
+    act(() => {
+      setMedia({
+        width: MOBILE_BREAKPOINT,
+      });
+    });
+
+    view.rerender(
+      <Provider store={store}>
+        <WebComponentProject
+          withSidebar={true}
+          sidebarOptions={["file", "images"]}
+        />
+      </Provider>,
+    );
+
+    fireEvent.click(screen.getByText("mobile.menu"));
+    expect(screen.queryByText("imagePanel.gallery")).toBeInTheDocument();
+
+    act(() => {
+      setMedia({
+        width: "1000px",
+      });
+    });
+
+    view.rerender(
+      <Provider store={store}>
+        <WebComponentProject
+          withSidebar={true}
+          sidebarOptions={["file", "images"]}
+        />
+      </Provider>,
+    );
+
+    expect(screen.queryByText("imagePanel.gallery")).toBeInTheDocument();
+  });
+
+  test("Keeps the sidebar collapsed when persisted as null", () => {
+    setMedia({
+      width: "1000px",
+    });
+
+    renderWebComponentProjectWithRealStore({
+      props: { withSidebar: true, sidebarOptions: ["file", "images"] },
+      editorOverrides: { selectedSidebarOption: null },
+    });
+
+    expect(screen.queryByTitle("sidebar.expand")).toBeInTheDocument();
+    expect(screen.queryByText("filePanel.files")).not.toBeInTheDocument();
+  });
+});
+
 describe("When withProjectbar is true", () => {
   beforeEach(() => {
     renderWebComponentProject({
diff --git a/src/redux/EditorSlice.js b/src/redux/EditorSlice.js
index c4c1a3190..e3d5328b7 100644
--- a/src/redux/EditorSlice.js
+++ b/src/redux/EditorSlice.js
@@ -119,6 +119,7 @@ export const editorInitialState = {
   newFileModalShowing: false,
   renameFileModalShowing: false,
   sidebarShowing: true,
+  selectedSidebarOption: undefined,
   modals: {},
   errorDetails: {},
   runnerBeingLoaded: null | "pyodide" | "skulpt",
@@ -362,6 +363,9 @@ export const EditorSlice = createSlice({
     hideSidebar: (state) => {
       state.sidebarShowing = false;
     },
+    setSidebarOption: (state, action) => {
+      state.selectedSidebarOption = action.payload;
+    },
     disableTheming: (state) => {
       state.isThemeable = false;
     },
@@ -482,6 +486,7 @@ export const {
   closeRenameFileModal,
   showSidebar,
   hideSidebar,
+  setSidebarOption,
   disableTheming,
   setErrorDetails,
 } = EditorSlice.actions;