diff --git a/README.md b/README.md
index 500df95..89665eb 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@ kompatible SPFx-1.4.1-/React-15-Toolchain.
 - Auswahl einer nicht ausgeblendeten Liste aus dem aktuellen Web
 - dynamische Auswahl von Überschrift-, Inhalt-, Kategorie- und Sortierspalte
 - optionales Gruppieren nach Kategorien
+- Filter auf eine konkrete, aktuell in der Liste verwendete Kategorie
 - auf- oder absteigende Sortierung
 - initial vollständig geschlossen, erster Eintrag geöffnet oder alle Einträge geöffnet
 - wahlweise genau ein oder mehrere gleichzeitig geöffnete Bereiche
@@ -28,8 +29,10 @@ Es wird keine fachliche Liste provisioniert. Eine einfache FAQ-Liste kann beispi
 | `Category` | Auswahl oder Text | optionale Gruppierung |
 | `SortOrder` | Zahl | optionale Sortierung |
 
-Nach dem Hinzufügen des WebParts werden Liste und Spalten im Property Pane ausgewählt. Änderungen an den
-Listeneinträgen erscheinen beim nächsten Laden beziehungsweise Rendern der Seite automatisch.
+Nach dem Hinzufügen des WebParts werden Liste und Spalten im Property Pane ausgewählt. Sobald eine
+Kategorie-Spalte festgelegt ist, kann unter **Angezeigte Kategorie** entweder eine der aktuell verwendeten
+Kategorien oder **Alle Kategorien** ausgewählt werden. Änderungen an den Listeneinträgen erscheinen beim
+nächsten Laden beziehungsweise Rendern der Seite automatisch.
 
 ## Version und Build
 
@@ -59,4 +62,3 @@ werden entfernt.
 
 Die fachliche Vorlage ist das PnP Community Sample:
 https://github.com/pnp/sp-dev-fx-webparts/tree/main/samples/react-accordion-dynamic-section
-
diff --git a/package.json b/package.json
index cdf146a..2488b26 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {
-  "name": "accordion",
+  "name": "accordion-web-part",
   "version": "1.0.0",
   "private": true,
   "main": "lib/index.js",
diff --git a/src/webparts/accordion/AccordionDataService.ts b/src/webparts/accordion/AccordionDataService.ts
index 697c9b1..0d05a4b 100644
--- a/src/webparts/accordion/AccordionDataService.ts
+++ b/src/webparts/accordion/AccordionDataService.ts
@@ -36,7 +36,8 @@ export class AccordionDataService {
     contentField: string,
     categoryField: string,
     sortField: string,
-    sortAscending: boolean
+    sortAscending: boolean,
+    categoryValue: string
   ): Promise<IAccordionItem[]> {
     if (!this.isGuid(listId)) { return Promise.reject(new Error('Invalid list ID.')); }
     const fields: string[] = this.uniqueFields(['Id', titleField, contentField, categoryField]);
@@ -48,12 +49,36 @@ export class AccordionDataService {
       '?$select=' + fields.join(',') + '&$orderby=' + orderField + (sortAscending ? ' asc' : ' desc') + '&$top=5000';
     return this.context.spHttpClient.get(url, SPHttpClient.configurations.v1, { headers: this.headers })
       .then((response: SPHttpClientResponse): Promise<any> => this.ensureJson(response)) // tslint:disable-line:no-any
-      .then((payload: any): IAccordionItem[] => this.results(payload).map((item: any): IAccordionItem => ({ // tslint:disable-line:no-any
-        id: Number(item.Id),
-        title: this.toText(item[titleField]),
-        content: this.toText(item[contentField]),
-        category: categoryField ? this.toText(item[categoryField]) : ''
-      })));
+      .then((payload: any): IAccordionItem[] => this.results(payload) // tslint:disable-line:no-any
+        .filter((item: any): boolean => !categoryValue || // tslint:disable-line:no-any
+          this.toValues(item[categoryField]).indexOf(categoryValue) >= 0)
+        .map((item: any): IAccordionItem => ({ // tslint:disable-line:no-any
+          id: Number(item.Id),
+          title: this.toText(item[titleField]),
+          content: this.toText(item[contentField]),
+          category: categoryField ? this.toText(item[categoryField]) : ''
+        })));
+  }
+
+  public getCategoryValues(listId: string, categoryField: string): Promise<string[]> {
+    if (!this.isGuid(listId) || !this.isFieldName(categoryField)) { return Promise.resolve([]); }
+    const url: string = this.webUrl + "/_api/web/lists(guid'" + this.cleanGuid(listId) + "')/items" +
+      '?$select=' + categoryField + '&$top=5000';
+    return this.context.spHttpClient.get(url, SPHttpClient.configurations.v1, { headers: this.headers })
+      .then((response: SPHttpClientResponse): Promise<any> => this.ensureJson(response)) // tslint:disable-line:no-any
+      .then((payload: any): string[] => { // tslint:disable-line:no-any
+        const values: string[] = [];
+        const keys: { [key: string]: boolean } = {};
+        const items: any[] = this.results(payload); // tslint:disable-line:no-any
+        for (let i: number = 0; i < items.length; i++) {
+          const current: string[] = this.toValues(items[i][categoryField]);
+          for (let valueIndex: number = 0; valueIndex < current.length; valueIndex++) {
+            const key: string = current[valueIndex].toLocaleLowerCase();
+            if (!keys[key]) { keys[key] = true; values.push(current[valueIndex]); }
+          }
+        }
+        return values.sort((left: string, right: string): number => left.localeCompare(right));
+      });
   }
 
   private get webUrl(): string { return this.context.pageContext.web.absoluteUrl.replace(/\/$/, ''); }
@@ -88,6 +113,13 @@ export class AccordionDataService {
     return '';
   }
 
+  private toValues(value: any): string[] { // tslint:disable-line:no-any
+    if (value === undefined || value === null) { return []; }
+    const source: any[] = value && Array.isArray(value.results) ? value.results : [value]; // tslint:disable-line:no-any
+    return source.map((entry: any): string => this.toText(entry).trim()) // tslint:disable-line:no-any
+      .filter((entry: string): boolean => !!entry);
+  }
+
   private isSupportedField(type: string): boolean {
     return ['Text', 'Note', 'Choice', 'MultiChoice', 'Number', 'Integer', 'Boolean', 'DateTime', 'Computed'].indexOf(String(type)) >= 0;
   }
@@ -95,4 +127,3 @@ export class AccordionDataService {
   private isGuid(value: string): boolean { return /^[0-9a-f]{8}-[0-9a-f-]{27}$/i.test(this.cleanGuid(value)); }
   private cleanGuid(value: string): string { return String(value || '').replace(/[{}]/g, '').toLowerCase(); }
 }
-
diff --git a/src/webparts/accordion/AccordionWebPart.manifest.json b/src/webparts/accordion/AccordionWebPart.manifest.json
index 3dd3fad..dc6de07 100644
--- a/src/webparts/accordion/AccordionWebPart.manifest.json
+++ b/src/webparts/accordion/AccordionWebPart.manifest.json
@@ -20,6 +20,7 @@
       "titleField": "Title",
       "contentField": "",
       "categoryField": "",
+      "selectedCategory": "",
       "sortField": "Title",
       "sortAscending": true,
       "allowMultiple": false,
diff --git a/src/webparts/accordion/AccordionWebPart.ts b/src/webparts/accordion/AccordionWebPart.ts
index 309be56..e018c1a 100644
--- a/src/webparts/accordion/AccordionWebPart.ts
+++ b/src/webparts/accordion/AccordionWebPart.ts
@@ -25,6 +25,7 @@ export interface IAccordionWebPartProps {
   titleField: string;
   contentField: string;
   categoryField: string;
+  selectedCategory: string;
   sortField: string;
   sortAscending: boolean;
   allowMultiple: boolean;
@@ -36,15 +37,19 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
   private service: AccordionDataService;
   private lists: IAccordionListOption[] = [];
   private fields: IAccordionFieldOption[] = [];
+  private categories: string[] = [];
   private loadingLists: boolean = false;
   private loadingFields: boolean = false;
+  private loadingCategories: boolean = false;
   private requestVersion: number = 0;
   private disposed: boolean = false;
 
   protected onInit(): Promise<void> {
     this.service = new AccordionDataService(this.context);
     return super.onInit().then((): Promise<void> => this.loadLists())
-      .then((): Promise<void> => this.properties.listId ? this.loadFields(this.properties.listId) : Promise.resolve());
+      .then((): Promise<void> => this.properties.listId ? this.loadFields(this.properties.listId) : Promise.resolve())
+      .then((): Promise<void> => this.properties.listId && this.properties.categoryField
+        ? this.loadCategories(this.properties.listId, this.properties.categoryField) : Promise.resolve());
   }
 
   public render(): void {
@@ -60,7 +65,8 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
       this.properties.contentField,
       this.properties.categoryField || '',
       this.properties.sortField || this.properties.titleField,
-      this.properties.sortAscending !== false
+      this.properties.sortAscending !== false,
+      this.properties.selectedCategory || ''
     ).then((items: IAccordionItem[]): void => {
       if (this.disposed || version !== this.requestVersion) { return; }
       if (!items.length) { this.renderStatus(strings.EmptyMessage, false); return; }
@@ -94,6 +100,9 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
     if (this.properties.listId && !this.fields.length && !this.loadingFields) {
       this.loadFields(this.properties.listId);
     }
+    if (this.properties.listId && this.properties.categoryField && !this.categories.length && !this.loadingCategories) {
+      this.loadCategories(this.properties.listId, this.properties.categoryField);
+    }
   }
 
   protected onPropertyPaneFieldChanged(propertyPath: string, oldValue: any, newValue: any): void { // tslint:disable-line:no-any
@@ -102,10 +111,17 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
       this.properties.titleField = '';
       this.properties.contentField = '';
       this.properties.categoryField = '';
+      this.properties.selectedCategory = '';
       this.properties.sortField = '';
       this.fields = [];
+      this.categories = [];
       this.context.propertyPane.refresh();
       this.loadFields(String(newValue || '')).then((): void => this.render());
+    } else if (propertyPath === 'categoryField' && newValue !== oldValue) {
+      this.properties.selectedCategory = '';
+      this.categories = [];
+      this.context.propertyPane.refresh();
+      this.loadCategories(this.properties.listId, String(newValue || '')).then((): void => this.render());
     }
   }
 
@@ -114,8 +130,12 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
       key: field.internalName, text: field.title + ' (' + field.internalName + ')'
     }));
     const categoryOptions: IPropertyPaneDropdownOption[] = [{ key: '', text: strings.NoCategoryOption }];
+    const categoryValueOptions: IPropertyPaneDropdownOption[] = [{ key: '', text: strings.AllCategoriesOption }];
     const listOptions: IPropertyPaneDropdownOption[] = [{ key: '', text: strings.SelectOption }];
     for (let i: number = 0; i < fieldOptions.length; i++) { categoryOptions.push(fieldOptions[i]); }
+    for (let i: number = 0; i < this.categories.length; i++) {
+      categoryValueOptions.push({ key: this.categories[i], text: this.categories[i] });
+    }
     for (let i: number = 0; i < this.lists.length; i++) {
       listOptions.push({ key: this.lists[i].id, text: this.lists[i].title });
     }
@@ -142,6 +162,10 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
               label: strings.CategoryFieldLabel, options: categoryOptions,
               disabled: !this.properties.listId || this.loadingFields
             }),
+            PropertyPaneDropdown('selectedCategory', {
+              label: strings.CategoryFilterLabel, options: categoryValueOptions,
+              disabled: !this.properties.categoryField || this.loadingCategories
+            }),
             PropertyPaneDropdown('sortField', {
               label: strings.SortFieldLabel, options: fieldOptions,
               disabled: !this.properties.listId || this.loadingFields
@@ -200,6 +224,28 @@ export default class AccordionWebPart extends BaseClientSideWebPart<IAccordionWe
     });
   }
 
+  private loadCategories(listId: string, categoryField: string): Promise<void> {
+    if (!listId || !categoryField) {
+      this.categories = [];
+      this.loadingCategories = false;
+      this.refreshPropertyPane();
+      return Promise.resolve();
+    }
+    this.loadingCategories = true;
+    this.refreshPropertyPane();
+    return this.service.getCategoryValues(listId, categoryField).then((categories: string[]): void => {
+      this.categories = categories;
+      if (categories.indexOf(this.properties.selectedCategory) < 0) { this.properties.selectedCategory = ''; }
+    }).catch((error: Error): void => {
+      this.categories = [];
+      this.properties.selectedCategory = '';
+      if (window.console) { console.error('[Accordion] Categories could not be loaded.', error); }
+    }).then((): void => {
+      this.loadingCategories = false;
+      this.refreshPropertyPane();
+    });
+  }
+
   private applyFieldDefaults(): void {
     const names: string[] = this.fields.map((field: IAccordionFieldOption): string => field.internalName);
     if (names.indexOf(this.properties.titleField) < 0) {
diff --git a/src/webparts/accordion/loc/de-de.js b/src/webparts/accordion/loc/de-de.js
index b586049..4f3cdcb 100644
--- a/src/webparts/accordion/loc/de-de.js
+++ b/src/webparts/accordion/loc/de-de.js
@@ -7,6 +7,7 @@ define([], function() {
     "TitleFieldLabel": "Spalte für Überschrift",
     "ContentFieldLabel": "Spalte für Inhalt",
     "CategoryFieldLabel": "Spalte für Kategorie (optional)",
+    "CategoryFilterLabel": "Angezeigte Kategorie",
     "SortFieldLabel": "Sortierspalte",
     "SortAscendingLabel": "Aufsteigend sortieren",
     "AllowMultipleLabel": "Mehrere geöffnete Bereiche erlauben",
@@ -17,6 +18,7 @@ define([], function() {
     "ShowCategoriesLabel": "Kategorieüberschriften anzeigen",
     "SelectOption": "Auswählen...",
     "NoCategoryOption": "Keine Kategorien",
+    "AllCategoriesOption": "Alle Kategorien",
     "ConfigureMessage": "Konfigurieren Sie in den WebPart-Einstellungen eine Liste sowie Überschrift- und Inhaltsspalte.",
     "LoadingMessage": "Akkordeon wird geladen...",
     "EmptyMessage": "Es wurden keine Einträge gefunden.",
@@ -26,4 +28,3 @@ define([], function() {
     "DefaultCategory": "Weitere"
   };
 });
-
diff --git a/src/webparts/accordion/loc/en-us.js b/src/webparts/accordion/loc/en-us.js
index 93ecad5..565638d 100644
--- a/src/webparts/accordion/loc/en-us.js
+++ b/src/webparts/accordion/loc/en-us.js
@@ -7,6 +7,7 @@ define([], function() {
     "TitleFieldLabel": "Heading column",
     "ContentFieldLabel": "Content column",
     "CategoryFieldLabel": "Category column (optional)",
+    "CategoryFilterLabel": "Displayed category",
     "SortFieldLabel": "Sort column",
     "SortAscendingLabel": "Sort ascending",
     "AllowMultipleLabel": "Allow multiple open sections",
@@ -17,6 +18,7 @@ define([], function() {
     "ShowCategoriesLabel": "Show category headings",
     "SelectOption": "Select...",
     "NoCategoryOption": "No categories",
+    "AllCategoriesOption": "All categories",
     "ConfigureMessage": "Configure a list, heading column and content column in the web part settings.",
     "LoadingMessage": "Loading accordion...",
     "EmptyMessage": "No entries were found.",
@@ -26,4 +28,3 @@ define([], function() {
     "DefaultCategory": "Other"
   };
 });
-
diff --git a/src/webparts/accordion/loc/myStrings.d.ts b/src/webparts/accordion/loc/myStrings.d.ts
index 4f7cf73..416e316 100644
--- a/src/webparts/accordion/loc/myStrings.d.ts
+++ b/src/webparts/accordion/loc/myStrings.d.ts
@@ -6,6 +6,7 @@ declare interface IAccordionWebPartStrings {
   TitleFieldLabel: string;
   ContentFieldLabel: string;
   CategoryFieldLabel: string;
+  CategoryFilterLabel: string;
   SortFieldLabel: string;
   SortAscendingLabel: string;
   AllowMultipleLabel: string;
@@ -16,6 +17,7 @@ declare interface IAccordionWebPartStrings {
   ShowCategoriesLabel: string;
   SelectOption: string;
   NoCategoryOption: string;
+  AllCategoriesOption: string;
   ConfigureMessage: string;
   LoadingMessage: string;
   EmptyMessage: string;
diff --git a/tests/validate-project.js b/tests/validate-project.js
index 9db5870..9e44cbc 100644
--- a/tests/validate-project.js
+++ b/tests/validate-project.js
@@ -27,6 +27,9 @@ assert(!!config.bundles['accordion-web-part'], 'Accordion bundle is missing.');
 assert(webPart.indexOf("PropertyPaneDropdown('listId'") >= 0, 'Dynamic list selection is missing.');
 assert(webPart.indexOf("PropertyPaneDropdown('contentField'") >= 0, 'Dynamic content field selection is missing.');
 assert(webPart.indexOf("PropertyPaneDropdown('categoryField'") >= 0, 'Category field selection is missing.');
+assert(webPart.indexOf("PropertyPaneDropdown('selectedCategory'") >= 0, 'Category value filter is missing.');
+assert(read('src/webparts/accordion/AccordionDataService.ts').indexOf('getCategoryValues') >= 0,
+  'Dynamic category values are missing.');
 assert(component.indexOf("aria-expanded={open}") >= 0 && component.indexOf("role='region'") >= 0,
   'Accessible accordion semantics are missing.');
 assert(component.indexOf('sanitizeAccordionHtml(item.content)') >= 0, 'Rich text is not sanitized before rendering.');