diff --git a/pkg/connector/client.go b/pkg/connector/client.go
index 2e80b72..728ac85 100644
--- a/pkg/connector/client.go
+++ b/pkg/connector/client.go
@@ -34,7 +34,7 @@ func NewClient(userLogin *bridgev2.UserLogin, client *gchatmeow.Client) *GChatCl
 		userLogin: userLogin,
 		client:    client,
 		users:     map[string]*proto.User{},
-		msgConv:   msgconv.NewMessageConverter(client),
+		msgConv:   msgconv.NewMessageConverter(userLogin.Bridge, client),
 	}
 }
 
diff --git a/pkg/gchatmeow/proto/extra.go b/pkg/gchatmeow/proto/extra.go
new file mode 100644
index 0000000..93a954a
--- /dev/null
+++ b/pkg/gchatmeow/proto/extra.go
@@ -0,0 +1,3 @@
+package proto
+
+type MetadataAssociatedValue = isAnnotation_Metadata
diff --git a/pkg/msgconv/from-matrix.go b/pkg/msgconv/from-matrix.go
index 726a184..3ec5261 100644
--- a/pkg/msgconv/from-matrix.go
+++ b/pkg/msgconv/from-matrix.go
@@ -13,7 +13,6 @@ func (mc *MessageConverter) ToGChat(
 	ctx context.Context,
 	content *event.MessageEventContent,
 ) (string, []*proto.Annotation) {
-	parser := &matrixfmt.HTMLParser{}
-	body, annotations := matrixfmt.Parse(ctx, parser, content)
+	body, annotations := matrixfmt.Parse(ctx, mc.matrixFmtParams, content)
 	return body, annotations
 }
diff --git a/pkg/msgconv/gchatfmt/utils.go b/pkg/msgconv/gchatfmt/utils.go
index 9781867..72e4513 100644
--- a/pkg/msgconv/gchatfmt/utils.go
+++ b/pkg/msgconv/gchatfmt/utils.go
@@ -14,5 +14,15 @@ func MakeAnnotation(start, length int32, format proto.FormatMetadata_FormatType)
 			},
 		},
 	}
+}
+
+func MakeAnnotationFromMetadata(typ proto.AnnotationType, start, length int32, metadata proto.MetadataAssociatedValue) *proto.Annotation {
+	return &proto.Annotation{
+		Type:           typ,
+		StartIndex:     start,
+		Length:         length,
+		ChipRenderType: proto.Annotation_DO_NOT_RENDER,
+		Metadata:       metadata,
+	}
 
 }
diff --git a/pkg/msgconv/matrixfmt/html.go b/pkg/msgconv/matrixfmt/html.go
index d3974c0..2101a2a 100644
--- a/pkg/msgconv/matrixfmt/html.go
+++ b/pkg/msgconv/matrixfmt/html.go
@@ -4,11 +4,13 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"slices"
 	"strconv"
 	"strings"
 
 	"golang.org/x/net/html"
 	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
 
 	"go.mau.fi/mautrix-googlechat/pkg/gchatmeow"
 )
@@ -228,7 +230,7 @@ func (ctx Context) WithWhitespace() Context {
 
 // HTMLParser is a somewhat customizable Matrix HTML parser.
 type HTMLParser struct {
-	// GetUUIDFromMXID func(context.Context, id.UserID) uuid.UUID
+	GetUIDFromMXID func(context.Context, id.UserID) string
 }
 
 // TaggedString is a string that also contains a HTML tag.
@@ -345,6 +347,21 @@ func (parser *HTMLParser) linkToString(node *html.Node, ctx Context) *EntityStri
 	if len(href) == 0 {
 		return str
 	}
+	parsedMatrix, err := id.ParseMatrixURIOrMatrixToURL(href)
+	if err == nil && parsedMatrix != nil && parsedMatrix.Sigil1 == '@' {
+		mxid := parsedMatrix.UserID()
+		if ctx.AllowedMentions != nil && !slices.Contains(ctx.AllowedMentions.UserIDs, mxid) {
+			// Mention not allowed, use name as-is
+			return str
+		}
+		u := parser.GetUIDFromMXID(ctx.Ctx, mxid)
+		if u == "" {
+			return str
+		}
+		return NewEntityString("@" + str.String.String()).Format(Mention{
+			ID: u,
+		})
+	}
 	if str.String.String() == href {
 		return str
 	}
diff --git a/pkg/msgconv/matrixfmt/tags.go b/pkg/msgconv/matrixfmt/tags.go
index 8f45c26..d39d7e2 100644
--- a/pkg/msgconv/matrixfmt/tags.go
+++ b/pkg/msgconv/matrixfmt/tags.go
@@ -9,7 +9,30 @@ import (
 type BodyRangeValue interface {
 	String() string
 	Format(message string) string
-	Proto() proto.FormatMetadata_FormatType
+	Proto() proto.MetadataAssociatedValue
+}
+
+type Mention struct {
+	ID string
+}
+
+func (m Mention) String() string {
+	return fmt.Sprintf("Mention{ID: (%s)}", m.ID)
+}
+
+func (m Mention) Proto() proto.MetadataAssociatedValue {
+	return &proto.Annotation_UserMentionMetadata{
+		UserMentionMetadata: &proto.UserMentionMetadata{
+			Type: proto.UserMentionMetadata_MENTION,
+			Id: &proto.UserId{
+				Id: m.ID,
+			},
+		},
+	}
+}
+
+func (m Mention) Format(message string) string {
+	return message
 }
 
 type Style int
@@ -27,8 +50,12 @@ const (
 	StyleFontColor
 )
 
-func (s Style) Proto() proto.FormatMetadata_FormatType {
-	return proto.FormatMetadata_FormatType(s)
+func (s Style) Proto() proto.MetadataAssociatedValue {
+	return &proto.Annotation_FormatMetadata{
+		FormatMetadata: &proto.FormatMetadata{
+			FormatType: proto.FormatMetadata_FormatType(s),
+		},
+	}
 }
 
 func (s Style) String() string {
diff --git a/pkg/msgconv/matrixfmt/tree.go b/pkg/msgconv/matrixfmt/tree.go
index 70a58b2..096cda8 100644
--- a/pkg/msgconv/matrixfmt/tree.go
+++ b/pkg/msgconv/matrixfmt/tree.go
@@ -63,7 +63,13 @@ func (b BodyRange) TruncateEnd(maxEnd int) *BodyRange {
 }
 
 func (b BodyRange) Proto() *proto.Annotation {
-	return gchatfmt.MakeAnnotation(int32(b.Start), int32(b.Length), b.Value.Proto())
+	metadata := b.Value.Proto()
+	typ := proto.AnnotationType_FORMAT_DATA
+	_, ok := metadata.(*proto.Annotation_UserMentionMetadata)
+	if ok {
+		typ = proto.AnnotationType_USER_MENTION
+	}
+	return gchatfmt.MakeAnnotationFromMetadata(typ, int32(b.Start), int32(b.Length), b.Value.Proto())
 }
 
 // LinkedRangeTree is a linked tree of formatting entities.
diff --git a/pkg/msgconv/msgconv.go b/pkg/msgconv/msgconv.go
index 94846f0..d72c2ae 100644
--- a/pkg/msgconv/msgconv.go
+++ b/pkg/msgconv/msgconv.go
@@ -1,15 +1,51 @@
 package msgconv
 
 import (
+	"context"
+
 	"go.mau.fi/mautrix-googlechat/pkg/gchatmeow"
+	"go.mau.fi/mautrix-googlechat/pkg/msgconv/matrixfmt"
+	"maunium.net/go/mautrix/bridgev2"
+	"maunium.net/go/mautrix/id"
+)
+
+type contextKey int
+
+const (
+	contextKeyPortal contextKey = iota
+	contextKeyClient
+	contextKeyIntent
 )
 
 type MessageConverter struct {
 	client *gchatmeow.Client
+
+	matrixFmtParams *matrixfmt.HTMLParser
 }
 
-func NewMessageConverter(client *gchatmeow.Client) *MessageConverter {
+func NewMessageConverter(br *bridgev2.Bridge, client *gchatmeow.Client) *MessageConverter {
 	return &MessageConverter{
 		client: client,
+
+		matrixFmtParams: &matrixfmt.HTMLParser{
+			GetUIDFromMXID: func(ctx context.Context, userID id.UserID) string {
+				parsed, ok := br.Matrix.ParseGhostMXID(userID)
+				if ok {
+					return string(parsed)
+				}
+				user, _ := br.GetExistingUserByMXID(ctx, userID)
+				if user != nil {
+					preferredLogin, _, _ := getPortal(ctx).FindPreferredLogin(ctx, user, true)
+					if preferredLogin != nil {
+						return string(preferredLogin.ID)
+					}
+				}
+				return ""
+			},
+		},
 	}
 }
+
+func getPortal(ctx context.Context) *bridgev2.Portal {
+	return ctx.Value(contextKeyPortal).(*bridgev2.Portal)
+}