diff --git a/calendar/experiments/calendar/ext-calendar-utils.jsm b/calendar/experiments/calendar/ext-calendar-utils.jsm
index 139a866..61245f1 100644
--- a/calendar/experiments/calendar/ext-calendar-utils.jsm
+++ b/calendar/experiments/calendar/ext-calendar-utils.jsm
@@ -79,6 +79,7 @@ function convertCalendar(extension, calendar) {
     readOnly: calendar.readOnly,
     enabled: !calendar.getProperty("disabled"),
     color: calendar.getProperty("color") || "#A8C2E1",
+    identity: calendar.getProperty("imip.identity.key"),
   };
 
   if (isOwnCalendar(calendar, extension)) {
diff --git a/calendar/experiments/calendar/parent/ext-calendar-calendars.js b/calendar/experiments/calendar/parent/ext-calendar-calendars.js
index 79e432e..5bb3817 100644
--- a/calendar/experiments/calendar/parent/ext-calendar-calendars.js
+++ b/calendar/experiments/calendar/parent/ext-calendar-calendars.js
@@ -80,6 +80,16 @@ this.calendar_calendars = class extends ExtensionAPI {
             }
           },
           create: async function(createProperties) {
+            if (createProperties.identity) {
+              if (!context.extension.hasPermission("accountsRead")) {
+                throw new ExtensionError('Using identities requires the "accountsRead" permission');
+              }
+
+              if (!MailServices.accounts.allIdentities.some(i => i.key == createProperties.identity)) {
+                throw new ExtensionError(`Identity not found: ${createProperties.identity}`);
+              }
+            }
+
             let calendar = calmgr.createCalendar(
               createProperties.type,
               Services.io.newURI(createProperties.url)
@@ -89,9 +99,12 @@ this.calendar_calendars = class extends ExtensionAPI {
             }
 
             calendar.name = createProperties.name;
-            if (typeof createProperties.color != "undefined") {
+            if (createProperties.color != null) {
               calendar.setProperty("color", createProperties.color);
             }
+            if (createProperties.identity != null) {
+              calendar.setProperty("imip.identity.key", createProperties.identity);
+            }
 
             calmgr.registerCalendar(calendar);
 
@@ -110,6 +123,16 @@ this.calendar_calendars = class extends ExtensionAPI {
             if (updateProperties.url && !isOwnCalendar(calendar, context.extension)) {
               throw new ExtensionError("Cannot update url for foreign calendars");
             }
+            if (updateProperties.identity) {
+              if (!context.extension.hasPermission("accountsRead")) {
+                throw new ExtensionError('Using identities requires the "accountsRead" permission');
+              }
+
+              if (!MailServices.accounts.allIdentities.some(i => i.key == updateProperties.identity)) {
+                throw new ExtensionError(`Identity not found: ${updateProperties.identity}`);
+              }
+            }
+
 
             if (updateProperties.url) {
               calendar.uri = Services.io.newURI(updateProperties.url);
@@ -125,6 +148,10 @@ this.calendar_calendars = class extends ExtensionAPI {
               }
             }
 
+            if (updateProperties.identity != null) {
+              calendar.setProperty("imip.identity.key", updateProperties.identity);
+            }
+
             // TODO capabilities merging
           },
           remove: async function(id) {
@@ -211,6 +238,9 @@ this.calendar_calendars = class extends ExtensionAPI {
                     case "disabled":
                       fire.sync(converted, { enabled: !value });
                       break;
+                    case "imip.identity.key":
+                      fire.sync(converted, { identity: value });
+                      break;
                   }
                 },
               });
diff --git a/calendar/experiments/calendar/schema/calendar-calendars.json b/calendar/experiments/calendar/schema/calendar-calendars.json
index 0967eff..2f68788 100644
--- a/calendar/experiments/calendar/schema/calendar-calendars.json
+++ b/calendar/experiments/calendar/schema/calendar-calendars.json
@@ -13,6 +13,7 @@
           "url": { "type": "string" },
           "readOnly": { "type": "boolean" },
           "enabled": { "type": "boolean" },
+          "identity": { "type": "string", "optional": true },
           "color": { "type": "string", "optional": true },
           "capabilities": { "$ref": "CalendarCapabilities", "optional": true }
         }
@@ -25,6 +26,7 @@
           "url": { "type": "string" },
           "readOnly": { "type": "boolean" },
           "enabled": { "type": "boolean" },
+          "identity": { "type": "string", "optional": true },
           "color": { "type": "string", "optional": true }
         }
       },
@@ -128,6 +130,7 @@
               "url": { "type": "string" },
               "readOnly": { "type": "boolean", "optional": true },
               "enabled": { "type": "boolean", "optional": true },
+              "identity": { "type": "string", "optional": true },
               "color": { "type": "string", "optional": true },
               "capabilities": { "$ref": "CalendarCapabilities", "optional": true }
             }
@@ -148,6 +151,7 @@
               "url": { "type": "string", "optional": true },
               "readOnly": { "type": "boolean", "optional": true },
               "enabled": { "type": "boolean", "optional": true },
+              "identity": { "type": "string", "optional": true },
               "color": { "type": "string", "optional": true },
               "capabilities": { "$ref": "CalendarCapabilities", "optional": true }
             }