diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 32e8f0db0..2e07899cf 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -11,6 +11,9 @@
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="android.permission.GET_ACCOUNTS"/>
 
+    <uses-permission android:name="android.permission.READ_CALENDAR" />
+    <uses-permission android:name="android.permission.WRITE_CALENDAR" />
+
     <application
         android:name=".App"
         android:allowBackup="true"
diff --git a/app/src/main/kotlin/com/simplemobiletools/calendar/activities/MainActivity.kt b/app/src/main/kotlin/com/simplemobiletools/calendar/activities/MainActivity.kt
index 18e88940d..0db1b9246 100644
--- a/app/src/main/kotlin/com/simplemobiletools/calendar/activities/MainActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/calendar/activities/MainActivity.kt
@@ -90,6 +90,10 @@ class MainActivity : SimpleActivity(), NavigationListener {
             config.googleSync = false
         }
 
+        if (!hasCalendarPermission()) {
+            config.caldavSync = false
+        }
+
         if (isGoogleSyncActive()) {
             FetchGoogleEventsTask(applicationContext, googleSyncListener).execute()
         }
diff --git a/app/src/main/kotlin/com/simplemobiletools/calendar/activities/SettingsActivity.kt b/app/src/main/kotlin/com/simplemobiletools/calendar/activities/SettingsActivity.kt
index 221ae8138..3362efa2c 100644
--- a/app/src/main/kotlin/com/simplemobiletools/calendar/activities/SettingsActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/calendar/activities/SettingsActivity.kt
@@ -39,6 +39,7 @@ class SettingsActivity : SimpleActivity() {
     private val ACCOUNTS_PERMISSION = 2
     private val REQUEST_ACCOUNT_NAME = 3
     private val REQUEST_GOOGLE_PLAY_SERVICES = 4
+    private val CALENDAR_PERMISSION = 5
 
     lateinit var res: Resources
     private var mStoredPrimaryColor = 0
@@ -135,11 +136,23 @@ class SettingsActivity : SimpleActivity() {
     private fun setupCaldavSync() {
         settings_caldav_sync.isChecked = config.caldavSync
         settings_caldav_sync_holder.setOnClickListener {
-            settings_caldav_sync.toggle()
-            config.caldavSync = settings_caldav_sync.isChecked
+            if (config.caldavSync) {
+                toggleCaldavSync()
+            } else {
+                if (hasCalendarPermission()) {
+                    toggleCaldavSync()
+                } else {
+                    ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.WRITE_CALENDAR), CALENDAR_PERMISSION)
+                }
+            }
         }
     }
 
+    private fun toggleCaldavSync() {
+        settings_caldav_sync.toggle()
+        config.caldavSync = settings_caldav_sync.isChecked
+    }
+
     private fun toggleGoogleSync() {
         settings_google_sync.toggle()
 
@@ -438,6 +451,10 @@ class SettingsActivity : SimpleActivity() {
             } else {
                 disableGoogleSync()
             }
+        } else if (requestCode == CALENDAR_PERMISSION) {
+            if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                toggleCaldavSync()
+            }
         }
     }
 
diff --git a/app/src/main/kotlin/com/simplemobiletools/calendar/extensions/Context.kt b/app/src/main/kotlin/com/simplemobiletools/calendar/extensions/Context.kt
index 8f3fb59ea..34b55e48b 100644
--- a/app/src/main/kotlin/com/simplemobiletools/calendar/extensions/Context.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/calendar/extensions/Context.kt
@@ -1,5 +1,6 @@
 package com.simplemobiletools.calendar.extensions
 
+import android.Manifest
 import android.annotation.TargetApi
 import android.app.AlarmManager
 import android.app.Notification
@@ -9,10 +10,12 @@ import android.appwidget.AppWidgetManager
 import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.graphics.Color
 import android.net.ConnectivityManager
 import android.net.Uri
 import android.os.Build
+import android.support.v4.content.ContextCompat
 import android.support.v7.app.NotificationCompat
 import com.google.api.client.extensions.android.http.AndroidHttp
 import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential
@@ -35,6 +38,8 @@ import org.joda.time.DateTimeZone
 import java.text.SimpleDateFormat
 import java.util.*
 
+fun Context.hasCalendarPermission() = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_CALENDAR) == PackageManager.PERMISSION_GRANTED
+
 fun Context.updateWidgets() {
     val widgetsCnt = AppWidgetManager.getInstance(this).getAppWidgetIds(ComponentName(this, MyWidgetMonthlyProvider::class.java))
     if (widgetsCnt.isNotEmpty()) {