diff --git a/connection.go b/connection.go
index fd2b08c..6595991 100644
--- a/connection.go
+++ b/connection.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"sort"
 	"strings"
+	"sync"
 	"unsafe"
 )
 
@@ -220,7 +221,7 @@ func (c *Connection) TransitionTo(version uint32, ALPN string) {
 	c.CryptoStates = make(map[EncryptionLevel]*CryptoState)
 	c.CryptoStreams = make(map[PNSpace]*Stream)
 	c.CryptoStates[EncryptionLevelInitial] = NewInitialPacketProtection(c)
-	c.Streams = Streams{make(map[uint64]*Stream), &c.StreamInput}
+	c.Streams = Streams{streams: make(map[uint64]*Stream), lock: &sync.Mutex{}, input: &c.StreamInput}
 }
 func (c *Connection) CloseConnection(quicLayer bool, errCode uint16, reasonPhrase string) {
 	if quicLayer {
diff --git a/streams.go b/streams.go
index 6f8ee12..40e8914 100644
--- a/streams.go
+++ b/streams.go
@@ -3,6 +3,7 @@ package quictracker
 import (
 	"fmt"
 	"math"
+	"sync"
 )
 
 type StreamsType bool
@@ -45,13 +46,16 @@ type StreamInput struct {
 
 type Streams struct {
 	streams map[uint64]*Stream
-	input *Broadcaster
+	lock    *sync.Mutex
+	input   *Broadcaster
 }
 
 func (s Streams) Get(streamId uint64) *Stream {
+	s.lock.Lock()
 	if s.streams[streamId] == nil {
 		s.streams[streamId] = NewStream()
 	}
+	s.lock.Unlock()
 	return s.streams[streamId]
 }