diff --git a/src/components/flow/actions/setrunresult/SetRunResultForm.tsx b/src/components/flow/actions/setrunresult/SetRunResultForm.tsx
index ed68a9bbf..0ec1ea37e 100644
--- a/src/components/flow/actions/setrunresult/SetRunResultForm.tsx
+++ b/src/components/flow/actions/setrunresult/SetRunResultForm.tsx
@@ -173,6 +173,7 @@ export default class SetRunResultForm extends React.PureComponent<
             onChange={this.handleCategoryUpdate}
             entry={this.state.category}
             autocomplete={false}
+            maxLength={128}
             helpText={i18n.t(
               'forms.result_category_help',
               "An optional category for your result. For age, the value might be 17, but the category might be 'Young Adult'"
diff --git a/src/components/flow/actions/setrunresult/__snapshots__/SetRunResultForm.test.ts.snap b/src/components/flow/actions/setrunresult/__snapshots__/SetRunResultForm.test.ts.snap
index 78b2c6b90..29a7d3d2f 100644
--- a/src/components/flow/actions/setrunresult/__snapshots__/SetRunResultForm.test.ts.snap
+++ b/src/components/flow/actions/setrunresult/__snapshots__/SetRunResultForm.test.ts.snap
@@ -94,6 +94,7 @@ exports[`SetRunResultForm render should render 1`] = `
         }
       }
       helpText="An optional category for your result. For age, the value might be 17, but the category might be 'Young Adult'"
+      maxLength={128}
       name="Category"
       onChange={[Function]}
       placeholder="Optional"