diff --git a/flowcontrol/flow_control_manager.go b/internal/flowcontrol/flow_control_manager.go
similarity index 100%
rename from flowcontrol/flow_control_manager.go
rename to internal/flowcontrol/flow_control_manager.go
diff --git a/flowcontrol/flow_control_manager_test.go b/internal/flowcontrol/flow_control_manager_test.go
similarity index 100%
rename from flowcontrol/flow_control_manager_test.go
rename to internal/flowcontrol/flow_control_manager_test.go
diff --git a/flowcontrol/flow_controller.go b/internal/flowcontrol/flow_controller.go
similarity index 100%
rename from flowcontrol/flow_controller.go
rename to internal/flowcontrol/flow_controller.go
diff --git a/flowcontrol/flow_controller_test.go b/internal/flowcontrol/flow_controller_test.go
similarity index 100%
rename from flowcontrol/flow_controller_test.go
rename to internal/flowcontrol/flow_controller_test.go
diff --git a/flowcontrol/flowcontrol_suite_test.go b/internal/flowcontrol/flowcontrol_suite_test.go
similarity index 100%
rename from flowcontrol/flowcontrol_suite_test.go
rename to internal/flowcontrol/flowcontrol_suite_test.go
diff --git a/flowcontrol/interface.go b/internal/flowcontrol/interface.go
similarity index 100%
rename from flowcontrol/interface.go
rename to internal/flowcontrol/interface.go
diff --git a/internal/mocks/gen.go b/internal/mocks/gen.go
index e77844769..7e0cc7cca 100644
--- a/internal/mocks/gen.go
+++ b/internal/mocks/gen.go
@@ -1,4 +1,4 @@
 package mocks
 
-//go:generate mockgen -destination mocks_fc/flow_control_manager.go -package mocks_fc github.com/lucas-clemente/quic-go/flowcontrol FlowControlManager
+//go:generate mockgen -destination mocks_fc/flow_control_manager.go -package mocks_fc github.com/lucas-clemente/quic-go/internal/flowcontrol FlowControlManager
 //go:generate mockgen -destination cpm.go -package mocks github.com/lucas-clemente/quic-go/handshake ConnectionParametersManager
diff --git a/internal/mocks/mocks_fc/flow_control_manager.go b/internal/mocks/mocks_fc/flow_control_manager.go
index 877a030e1..490fd9cac 100644
--- a/internal/mocks/mocks_fc/flow_control_manager.go
+++ b/internal/mocks/mocks_fc/flow_control_manager.go
@@ -1,11 +1,11 @@
 // Automatically generated by MockGen. DO NOT EDIT!
-// Source: github.com/lucas-clemente/quic-go/flowcontrol (interfaces: FlowControlManager)
+// Source: github.com/lucas-clemente/quic-go/internal/flowcontrol (interfaces: FlowControlManager)
 
 package mocks_fc
 
 import (
 	gomock "github.com/golang/mock/gomock"
-	flowcontrol "github.com/lucas-clemente/quic-go/flowcontrol"
+	flowcontrol "github.com/lucas-clemente/quic-go/internal/flowcontrol"
 	protocol "github.com/lucas-clemente/quic-go/internal/protocol"
 )
 
diff --git a/session.go b/session.go
index baa748af5..14f5425ba 100644
--- a/session.go
+++ b/session.go
@@ -11,8 +11,8 @@ import (
 
 	"github.com/lucas-clemente/quic-go/ackhandler"
 	"github.com/lucas-clemente/quic-go/congestion"
-	"github.com/lucas-clemente/quic-go/flowcontrol"
 	"github.com/lucas-clemente/quic-go/handshake"
+	"github.com/lucas-clemente/quic-go/internal/flowcontrol"
 	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/internal/utils"
 	"github.com/lucas-clemente/quic-go/internal/wire"
diff --git a/stream.go b/stream.go
index cf3446824..41c8e1054 100644
--- a/stream.go
+++ b/stream.go
@@ -8,7 +8,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/lucas-clemente/quic-go/flowcontrol"
+	"github.com/lucas-clemente/quic-go/internal/flowcontrol"
 	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/internal/utils"
 	"github.com/lucas-clemente/quic-go/internal/wire"
diff --git a/stream_framer.go b/stream_framer.go
index e71754257..d5916c211 100644
--- a/stream_framer.go
+++ b/stream_framer.go
@@ -1,7 +1,7 @@
 package quic
 
 import (
-	"github.com/lucas-clemente/quic-go/flowcontrol"
+	"github.com/lucas-clemente/quic-go/internal/flowcontrol"
 	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/internal/utils"
 	"github.com/lucas-clemente/quic-go/internal/wire"