diff --git a/src/structures/DMChannel.js b/src/structures/DMChannel.js
index 063c07286..f78dd3684 100644
--- a/src/structures/DMChannel.js
+++ b/src/structures/DMChannel.js
@@ -24,6 +24,10 @@ class DMChannel extends Channel {
      */
     this.recipient = this.client.dataManager.newUser(data.recipients[0]);
 
+    /**
+     * The ID of the last message in the channel, if one was sent
+     * @type {?Snowflake}
+     */
     this.lastMessageID = data.last_message_id;
   }
 
diff --git a/src/structures/GroupDMChannel.js b/src/structures/GroupDMChannel.js
index 0bbfd6120..146ba1ff8 100644
--- a/src/structures/GroupDMChannel.js
+++ b/src/structures/GroupDMChannel.js
@@ -94,6 +94,10 @@ class GroupDMChannel extends Channel {
       }
     }
 
+    /**
+     * The ID of the last message in the channel, if one was sent
+     * @type {?Snowflake}
+     */
     this.lastMessageID = data.last_message_id;
   }
 
diff --git a/src/structures/TextChannel.js b/src/structures/TextChannel.js
index dcaa3d97d..20b9d4970 100644
--- a/src/structures/TextChannel.js
+++ b/src/structures/TextChannel.js
@@ -31,6 +31,10 @@ class TextChannel extends GuildChannel {
      */
     this.nsfw = Boolean(data.nsfw);
 
+    /**
+     * The ID of the last message sent in this channel, if one was sent
+     * @type {?Snowflake}
+     */
     this.lastMessageID = data.last_message_id;
   }