diff --git a/CHANGELOG.md b/CHANGELOG.md
index c140bb6..40b7eb3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 ### Improvements
 
 ### Changes
+- allow `.` in mentions (like `@bsky.brid.gy@bsky.brid.gy`)
 
 ### Bugfixes
 
diff --git a/src/internal/parser.ts b/src/internal/parser.ts
index 26029b1..5b8eac4 100644
--- a/src/internal/parser.ts
+++ b/src/internal/parser.ts
@@ -552,7 +552,7 @@ export const language = P.createLanguage<TypeTable>({
 		const parser = P.seq(
 			notLinkLabel,
 			P.str('@'),
-			P.regexp(/[a-z0-9_-]+/i),
+			P.regexp(/[a-z0-9_.-]+/i),
 			P.seq(
 				P.str('@'),
 				P.regexp(/[a-z0-9_.-]+/i),
@@ -586,9 +586,9 @@ export const language = P.createLanguage<TypeTable>({
 					}
 				}
 			}
-			// remove "-" of tail of username
+			// remove [.-] of tail of username
 			let modifiedName = username;
-			result = /-+$/.exec(username);
+			result = /[.-]+$/.exec(username);
 			if (result != null) {
 				if (modifiedHost == null) {
 					modifiedName = username.slice(0, (-1 * result[0].length));
@@ -597,8 +597,8 @@ export const language = P.createLanguage<TypeTable>({
 					invalidMention = true;
 				}
 			}
-			// disallow "-" of head of username
-			if (modifiedName.length === 0 || modifiedName[0] === '-') {
+			// disallow [.-] of head of username
+			if (modifiedName.length === 0 || /^[.-]/.test(modifiedName)) {
 				invalidMention = true;
 			}
 			// disallow [.-] of head of hostname
diff --git a/test/parser.ts b/test/parser.ts
index 852699c..36d98c3 100644
--- a/test/parser.ts
+++ b/test/parser.ts
@@ -733,6 +733,12 @@ hoge`;
 			assert.deepStrictEqual(mfm.parse(input), output);
 		});
 
+		test('allow "." in username', () => {
+			const input = '@bsky.brid.gy@bsky.brid.gy';
+			const output = [MENTION('bsky.brid.gy', 'bsky.brid.gy', '@bsky.brid.gy@bsky.brid.gy')];
+			assert.deepStrictEqual(mfm.parse(input), output);
+		});
+
 		test('disallow "-" in head of username', () => {
 			const input = '@-abc';
 			const output = [TEXT('@-abc')];
@@ -745,6 +751,18 @@ hoge`;
 			assert.deepStrictEqual(mfm.parse(input), output);
 		});
 
+		test('disallow "." in head of username', () => {
+			const input = '@.abc';
+			const output = [TEXT('@.abc')];
+			assert.deepStrictEqual(mfm.parse(input), output);
+		});
+
+		test('disallow "." in tail of username', () => {
+			const input = '@abc.';
+			const output = [MENTION('abc', null, '@abc'), TEXT('.')];
+			assert.deepStrictEqual(mfm.parse(input), output);
+		});
+
 		test('disallow "." in head of hostname', () => {
 			const input = '@abc@.aaa';
 			const output = [TEXT('@abc@.aaa')];