diff --git a/src/Client.hh b/src/Client.hh
index c8d19576..c13e065c 100644
--- a/src/Client.hh
+++ b/src/Client.hh
@@ -3,7 +3,6 @@
 #include <netinet/in.h>
 
 #include <memory>
-#include <phosg/Concurrency.hh>
 
 #include "License.hh"
 #include "Player.hh"
diff --git a/src/License.hh b/src/License.hh
index 927870fd..d6514d66 100644
--- a/src/License.hh
+++ b/src/License.hh
@@ -1,6 +1,5 @@
 #pragma once
 
-#include <phosg/Concurrency.hh>
 #include <unordered_map>
 #include <string>
 
diff --git a/src/Lobby.hh b/src/Lobby.hh
index 51737350..b4b1d9ef 100644
--- a/src/Lobby.hh
+++ b/src/Lobby.hh
@@ -3,7 +3,6 @@
 #include <inttypes.h>
 
 #include <vector>
-#include <phosg/Concurrency.hh>
 
 #include "Client.hh"
 #include "Player.hh"
diff --git a/src/ServerState.hh b/src/ServerState.hh
index 0218868f..3d44dd32 100644
--- a/src/ServerState.hh
+++ b/src/ServerState.hh
@@ -5,7 +5,6 @@
 #include <unordered_map>
 #include <string>
 #include <memory>
-#include <phosg/Concurrency.hh>
 #include <vector>
 #include <set>