diff --git a/src/public/app/layouts/desktop_layout.ts b/src/public/app/layouts/desktop_layout.ts
index 548d1c3d9..9d8a06ac1 100644
--- a/src/public/app/layouts/desktop_layout.ts
+++ b/src/public/app/layouts/desktop_layout.ts
@@ -90,6 +90,7 @@ import CloseZenButton from "../widgets/close_zen_button.js";
 import type { AppContext } from "./../components/app_context.js";
 import type { WidgetsByParent } from "../services/bundle.js";
 import SwitchSplitOrientationButton from "../widgets/floating_buttons/switch_layout_button.js";
+import ToggleReadOnlyButton from "../widgets/floating_buttons/toggle_read_only_button.js";
 
 export default class DesktopLayout {
 
@@ -204,6 +205,7 @@ export default class DesktopLayout {
                                                         .child(
                                                             new FloatingButtons()
                                                                 .child(new SwitchSplitOrientationButton())
+                                                                .child(new ToggleReadOnlyButton())
                                                                 .child(new EditButton())
                                                                 .child(new ShowTocWidgetButton())
                                                                 .child(new ShowHighlightsListWidgetButton())
diff --git a/src/public/app/services/attributes.ts b/src/public/app/services/attributes.ts
index b47e297cd..8de409e9b 100644
--- a/src/public/app/services/attributes.ts
+++ b/src/public/app/services/attributes.ts
@@ -23,6 +23,23 @@ async function removeAttributeById(noteId: string, attributeId: string) {
     await server.remove(`notes/${noteId}/attributes/${attributeId}`);
 }
 
+/**
+ * Removes a label identified by its name from the given note, if it exists. Note that the label must be owned, i.e.
+ * it will not remove inherited attributes.
+ *
+ * @param note the note from which to remove the label.
+ * @param labelName the name of the label to remove.
+ * @returns `true` if an attribute was identified and removed, `false` otherwise.
+ */
+function removeOwnedLabelByName(note: FNote, labelName: string) {
+    const label = note.getOwnedLabel(labelName);
+    if (label) {
+        removeAttributeById(note.noteId, label.attributeId);
+        return true;
+    }
+    return false;
+}
+
 /**
  * Sets the attribute of the given note to the provided value if its truthy, or removes the attribute if the value is falsy.
  * For an attribute with an empty value, pass an empty string instead.
@@ -90,5 +107,6 @@ export default {
     setLabel,
     setAttribute,
     removeAttributeById,
+    removeOwnedLabelByName,
     isAffecting
 };
diff --git a/src/public/app/widgets/floating_buttons/toggle_read_only_button.ts b/src/public/app/widgets/floating_buttons/toggle_read_only_button.ts
new file mode 100644
index 000000000..f6b159243
--- /dev/null
+++ b/src/public/app/widgets/floating_buttons/toggle_read_only_button.ts
@@ -0,0 +1,45 @@
+import type FNote from "../../entities/fnote.js";
+import attributes from "../../services/attributes.js";
+import { t } from "../../services/i18n.js";
+import OnClickButtonWidget from "../buttons/onclick_button.js";
+
+export default class ToggleReadOnlyButton extends OnClickButtonWidget {
+
+    private isReadOnly?: boolean;
+
+    constructor() {
+        super();
+
+        this
+            .title(() => this.isReadOnly ? t("toggle_read_only_button.unlock-editing") : t("toggle_read_only_button.lock-editing"))
+            .titlePlacement("bottom")
+            .icon(() => this.isReadOnly ? "bx-lock-open-alt" : "bx-lock-alt")
+            .onClick(() => this.#toggleReadOnly());
+    }
+
+    #toggleReadOnly() {
+        if (!this.noteId || !this.note) {
+            return;
+        }
+
+        if (this.isReadOnly) {
+            attributes.removeOwnedLabelByName(this.note, "readOnly");
+        } else {
+            attributes.setLabel(this.noteId, "readOnly");
+        }
+    }
+
+    async refreshWithNote(note: FNote | null | undefined) {
+        const isReadOnly = !!note?.hasLabel("readOnly");
+
+        if (isReadOnly !== this.isReadOnly) {
+            this.isReadOnly = isReadOnly;
+            this.refreshIcon();
+        }
+    }
+
+    isEnabled() {
+        return super.isEnabled() && this.note?.type === "mermaid";
+    }
+
+}
diff --git a/src/public/translations/en/translation.json b/src/public/translations/en/translation.json
index 99d9b48b1..da4751e36 100644
--- a/src/public/translations/en/translation.json
+++ b/src/public/translations/en/translation.json
@@ -1707,5 +1707,9 @@
   "switch_layout_button": {
     "title_vertical": "Move editing pane to the bottom",
     "title_horizontal": "Move editing pane to the left"
+  },
+  "toggle_read_only_button": {
+    "unlock-editing": "Unlock editing",
+    "lock-editing": "Lock editing"
   }
 }