diff --git a/css/src/style.scss b/css/src/style.scss
index d46650279..2f1720360 100644
--- a/css/src/style.scss
+++ b/css/src/style.scss
@@ -1,3 +1,5 @@
+@include icon-black-white('circle', 'tasks', 1);
+
 /**
 	* rules for app-navigation
 	*/
diff --git a/img/circle.svg b/img/circle.svg
new file mode 100644
index 000000000..0ebe00d47
--- /dev/null
+++ b/img/circle.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 57 57" width="64" height="64"><path d="M7 29A21 21 0 0 1 29 7m10 40a21 21 0 0 1-29-8m29-29a21 21 0 0 1 8 29" fill="none" stroke="#000" stroke-width="4" stroke-linecap="round" stroke-linejoin="round"/><circle cx="29" cy="7" r="7"/><circle cx="39" cy="-10" r="7" transform="rotate(90)"/><circle cx="39" cy="-47" r="7" transform="rotate(90)"/></svg>
diff --git a/package.json b/package.json
index 77b58be74..a2e4b2372 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,7 @@
 		"@vue/test-utils": "^1.0.0-beta.33",
 		"cdav-library": "github:nextcloud/cdav-library",
 		"color-convert": "^2.0.1",
+		"debounce": "^1.2.0",
 		"ical.js": "~1.4.0",
 		"jstimezonedetect": "",
 		"linkify-it": "~2.2.0",
diff --git a/src/components/AppNavigation/CalendarShare.vue b/src/components/AppNavigation/CalendarShare.vue
index b3cf6fd81..c77dfb68c 100644
--- a/src/components/AppNavigation/CalendarShare.vue
+++ b/src/components/AppNavigation/CalendarShare.vue
@@ -1,7 +1,12 @@
 <!--
 @copyright Copyright (c) 2018 Team Popcorn <teampopcornberlin@gmail.com>
+@copyright Copyright (c) 2019 Georg Ehrke <oc.list@georgehrke.com>
+@copyright Copyright (c) 2019 Jakob Röhrl <jakob.roehrl@web.de>
+@copyright Copyright (c) 2020 Raimund Schlüßler <raimund.schluessler@mailbox.org>
 
 @author Team Popcorn <teampopcornberlin@gmail.com>
+@author Georg Ehrke <oc.list@georgehrke.com>
+@author Jakob Röhrl <jakob.roehrl@web.de>
 @author Raimund Schlüßler <raimund.schluessler@mailbox.org>
 
 @license GNU AGPL version 3 or any later version
@@ -39,7 +44,7 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 					track-by="user"
 					label="user"
 					@search-change="findSharee"
-					@input="shareCalendar" />
+					@change="shareCalendar" />
 			</li>
 			<!-- list of user or groups calendar is shared with -->
 			<CalendarSharee v-for="sharee in calendar.shares"
@@ -51,11 +56,13 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 </template>
 
 <script>
+import CalendarSharee from './CalendarSharee'
 import client from '../../services/cdav'
-import Multiselect from '@nextcloud/vue/dist/Components/Multiselect'
 
-import CalendarSharee from './CalendarSharee'
-// import debounce from 'debounce'
+import HttpClient from '@nextcloud/axios'
+import { generateOcsUrl } from '@nextcloud/router'
+import Multiselect from '@nextcloud/vue/dist/Components/Multiselect'
+import debounce from 'debounce'
 
 export default {
 	name: 'CalendarShare',
@@ -95,48 +102,148 @@ export default {
 		 * Share calendar
 		 *
 		 * @param {Object} data destructuring object
-		 * @param {string} data.user the userId
-		 * @param {string} data.displayName the displayName
-		 * @param {string} data.uri the sharing principalScheme uri
-		 * @param {boolean} data.isGroup is this a group ?
+		 * @param {String} data.user the userId
+		 * @param {String} data.displayName the displayName
+		 * @param {String} data.uri the sharing principalScheme uri
+		 * @param {Boolean} data.isGroup is this a group ?
+		 * @param {Boolean} data.isCircle is this a circle?
 		 */
-		shareCalendar({ user, displayName, uri, isGroup }) {
+		shareCalendar({ user, displayName, uri, isGroup, isCircle }) {
 			const calendar = this.calendar
 			uri = decodeURI(uri)
 			user = decodeURI(user)
-			this.$store.dispatch('shareCalendar', { calendar, user, displayName, uri, isGroup })
+			this.$store.dispatch('shareCalendar', { calendar, user, displayName, uri, isGroup, isCircle })
 		},
 
 		/**
 		 * Use the cdav client call to find matches to the query from the existing Users & Groups
 		 *
-		 * @param {string} query The query string
+		 * @param {String} query
 		 */
-		async findSharee(query) {
+		findSharee: debounce(async function(query) {
+			const hiddenPrincipalSchemes = []
+			const hiddenUrls = []
+			this.calendar.shares.forEach((share) => {
+				hiddenPrincipalSchemes.push(share.uri)
+			})
+			if (this.$store.getters.getCurrentUserPrincipal) {
+				hiddenUrls.push(this.$store.getters.getCurrentUserPrincipal.url)
+			}
+			if (this.calendar.owner) {
+				hiddenUrls.push(this.calendar.owner)
+			}
+
 			this.isLoading = true
 			this.usersOrGroups = []
+
 			if (query.length > 0) {
-				const results = await client.principalPropertySearchByDisplayname(query)
-				this.usersOrGroups = results.reduce((list, result) => {
-					if (['GROUP', 'INDIVIDUAL'].indexOf(result.calendarUserType) > -1
-					&& !this.calendar.shares.some((share) => share.uri === result.principalScheme)) {
-						const isGroup = result.calendarUserType === 'GROUP'
-						list.push({
-							user: result[isGroup ? 'groupId' : 'userId'],
-							displayName: result.displayname,
-							icon: isGroup ? 'icon-group' : 'icon-user',
-							uri: result.principalScheme,
-							isGroup,
-						})
-					}
-					return list
-				}, [])
+				const davPromise = this.findShareesFromDav(query, hiddenPrincipalSchemes, hiddenUrls)
+				const ocsPromise = this.findShareesFromCircles(query, hiddenPrincipalSchemes, hiddenUrls)
+
+				const [davResults, ocsResults] = await Promise.all([davPromise, ocsPromise])
+				this.usersOrGroups = [
+					...davResults,
+					...ocsResults,
+				]
+
 				this.isLoading = false
 				this.inputGiven = true
 			} else {
 				this.inputGiven = false
 				this.isLoading = false
 			}
+		}, 500),
+		/**
+		 *
+		 * @param {String} query The search query
+		 * @param {String[]} hiddenPrincipals A list of principals to exclude from search results
+		 * @param {String[]} hiddenUrls A list of urls to exclude from search results
+		 * @returns {Promise<Object[]>}
+		 */
+		async findShareesFromDav(query, hiddenPrincipals, hiddenUrls) {
+			let results
+			try {
+				results = await client.principalPropertySearchByDisplayname(query)
+			} catch (error) {
+				return []
+			}
+
+			return results.reduce((list, result) => {
+				if (hiddenPrincipals.includes(decodeURI(result.principalScheme))) {
+					return list
+				}
+				if (hiddenUrls.includes(result.url)) {
+					return list
+				}
+
+				// Don't show resources and rooms
+				if (!['GROUP', 'INDIVIDUAL'].includes(result.calendarUserType)) {
+					return list
+				}
+
+				const isGroup = result.calendarUserType === 'GROUP'
+				list.push({
+					user: result[isGroup ? 'groupId' : 'userId'],
+					displayName: result.displayname,
+					icon: isGroup ? 'icon-group' : 'icon-user',
+					uri: result.principalScheme,
+					isGroup,
+					isCircle: false,
+					isNoUser: isGroup,
+					search: query,
+				})
+				return list
+			}, [])
+		},
+		/**
+		 *
+		 * @param {String} query The search query
+		 * @param {String[]} hiddenPrincipals A list of principals to exclude from search results
+		 * @param {String[]} hiddenUrls A list of urls to exclude from search results
+		 * @returns {Promise<Object[]>}
+		 */
+		async findShareesFromCircles(query, hiddenPrincipals, hiddenUrls) {
+			let results
+			try {
+				results = await HttpClient.get(generateOcsUrl('apps/files_sharing/api/v1') + 'sharees', {
+					params: {
+						format: 'json',
+						search: query,
+						perPage: 200,
+						itemType: 'principals',
+					},
+				})
+			} catch (error) {
+				return []
+			}
+
+			if (results.data.ocs.meta.status === 'failure') {
+				return []
+			}
+			let circles = []
+			if (Array.isArray(results.data.ocs.data.circles)) {
+				circles = circles.concat(results.data.ocs.data.circles)
+			}
+			if (Array.isArray(results.data.ocs.data.exact.circles)) {
+				circles = circles.concat(results.data.ocs.data.exact.circles)
+			}
+
+			if (circles.length === 0) {
+				return []
+			}
+
+			return circles.filter((circle) => {
+				return !hiddenPrincipals.includes('principal:principals/circles/' + circle.value.shareWith)
+			}).map(circle => ({
+				user: circle.label,
+				displayName: circle.label,
+				icon: 'icon-circle',
+				uri: 'principal:principals/circles/' + circle.value.shareWith,
+				isGroup: false,
+				isCircle: true,
+				isNoUser: true,
+				search: query,
+			}))
 		},
 	},
 }
diff --git a/src/store/calendars.js b/src/store/calendars.js
index 65f72d763..c3f3f7edf 100644
--- a/src/store/calendars.js
+++ b/src/store/calendars.js
@@ -127,14 +127,20 @@ export function mapDavCollectionToCalendar(calendar, currentUserPrincipal) {
  */
 export function mapDavShareeToSharee(sharee) {
 	const id = sharee.href.split('/').slice(-1)[0]
-	const name = sharee['common-name']
+	let name = sharee['common-name']
 		? sharee['common-name']
-		: id
+		: sharee.href
+
+	if (sharee.href.startsWith('principal:principals/groups/') && name === sharee.href) {
+		name = sharee.href.substr(28)
+	}
+
 	return {
 		displayName: name,
 		id,
 		writeable: sharee.access[0].endsWith('read-write'),
 		isGroup: sharee.href.startsWith('principal:principals/groups/'),
+		isCircle: sharee.href.startsWith('principal:principals/circles/'),
 		uri: sharee.href,
 	}
 }
@@ -391,14 +397,16 @@ const mutations = {
 	 * @param {String} data.displayName The displayName
 	 * @param {String} data.uri The sharing principalScheme uri
 	 * @param {Boolean} data.isGroup Is this a group ?
+	 * @param {Boolean} data.isCircle Is this a circle?
 	 */
-	shareCalendar(state, { calendar, user, displayName, uri, isGroup }) {
+	shareCalendar(state, { calendar, user, displayName, uri, isGroup, isCircle }) {
 		calendar = state.calendars.find(search => search.id === calendar.id)
 		const newSharee = {
 			displayName,
 			id: user,
 			writeable: false,
 			isGroup,
+			isCircle,
 			uri,
 		}
 		if (!calendar.shares.some((share) => share.uri === uri)) {
@@ -686,11 +694,12 @@ const actions = {
 	 * @param {String} data.displayName The displayName
 	 * @param {String} data.uri The sharing principalScheme uri
 	 * @param {Boolean} data.isGroup Is this a group ?
+	 * @param {Boolean} data.isCircle Is this a circle?
 	 */
-	async shareCalendar(context, { calendar, user, displayName, uri, isGroup }) {
+	async shareCalendar(context, { calendar, user, displayName, uri, isGroup, isCircle }) {
 		// Share calendar with entered group or user
 		await calendar.dav.share(uri)
-		context.commit('shareCalendar', { calendar, user, displayName, uri, isGroup })
+		context.commit('shareCalendar', { calendar, user, displayName, uri, isGroup, isCircle })
 	},
 }