diff --git a/src/remote/activitypub/models/person.ts b/src/remote/activitypub/models/person.ts
index a0b951c5f4..1c674729cb 100644
--- a/src/remote/activitypub/models/person.ts
+++ b/src/remote/activitypub/models/person.ts
@@ -134,7 +134,7 @@ export async function createPerson(uri: string, resolver?: Resolver): Promise<Us
 
 	const { fields } = analyzeAttachments(person.attachment || []);
 
-	const tags = extractHashtags(person.tag).map(tag => tag.toLowerCase());
+	const tags = extractHashtags(person.tag).map(tag => tag.toLowerCase()).splice(0, 100);
 
 	const isBot = object.type == 'Service';
 
@@ -307,7 +307,7 @@ export async function updatePerson(uri: string, resolver?: Resolver | null, hint
 
 	const { fields, services } = analyzeAttachments(person.attachment || []);
 
-	const tags = extractHashtags(person.tag).map(tag => tag.toLowerCase());
+	const tags = extractHashtags(person.tag).map(tag => tag.toLowerCase()).splice(0, 100);
 
 	const updates = {
 		lastFetchedAt: new Date(),
diff --git a/src/server/api/endpoints/i/update.ts b/src/server/api/endpoints/i/update.ts
index 91056f04a7..99f7efbe1c 100644
--- a/src/server/api/endpoints/i/update.ts
+++ b/src/server/api/endpoints/i/update.ts
@@ -257,7 +257,7 @@ export default define(meta, async (ps, user, app) => {
 	if (newDescription != null) {
 		const tokens = parse(newDescription);
 		emojis = emojis.concat(extractEmojis(tokens!));
-		tags = extractHashtags(tokens!).map(tag => tag.toLowerCase());
+		tags = extractHashtags(tokens!).map(tag => tag.toLowerCase()).splice(0, 100);
 	}
 
 	updates.emojis = emojis;
diff --git a/src/services/note/create.ts b/src/services/note/create.ts
index fcf991793b..0bb6cc1f5c 100644
--- a/src/services/note/create.ts
+++ b/src/services/note/create.ts
@@ -165,7 +165,7 @@ export default async (user: User, data: Option, silent = false) => new Promise<N
 		mentionedUsers = data.apMentions || await extractMentionedUsers(user, combinedTokens);
 	}
 
-	tags = tags.filter(tag => Array.from(tag || '').length <= 128);
+	tags = tags.filter(tag => Array.from(tag || '').length <= 128).splice(0, 100);
 
 	if (data.reply && (user.id !== data.reply.userId) && !mentionedUsers.some(u => u.id === data.reply!.userId)) {
 		mentionedUsers.push(await Users.findOne(data.reply.userId).then(ensure));