diff --git a/src/mess/drivers/mtx.c b/src/mess/drivers/mtx.c
index df1a4ee859f..f6839299480 100644
--- a/src/mess/drivers/mtx.c
+++ b/src/mess/drivers/mtx.c
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Lee Ward, Dirk Best, Curt Coder
 /*************************************************************************
 
diff --git a/src/mess/drivers/sms.c b/src/mess/drivers/sms.c
index 1a4d225a94a..bd7c6f37c8d 100644
--- a/src/mess/drivers/sms.c
+++ b/src/mess/drivers/sms.c
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Wilbert Pol, Charles MacDonald,Mathis Rosenhauer,Brad Oliver,Michael Luong,Fabio Priuli,Enik Land
 /******************************************************************************
  Contributors:
diff --git a/src/mess/drivers/z80ne.c b/src/mess/drivers/z80ne.c
index c7e52a248f3..f8e80e537a7 100644
--- a/src/mess/drivers/z80ne.c
+++ b/src/mess/drivers/z80ne.c
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Roberto Lavarone
 /******************************************************************************
     Nuova Elettronica Z80NE system driver
diff --git a/src/mess/includes/mtx.h b/src/mess/includes/mtx.h
index 9e852ed6e2d..5558e1fcd15 100644
--- a/src/mess/includes/mtx.h
+++ b/src/mess/includes/mtx.h
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Lee Ward, Dirk Best, Curt Coder
 /*************************************************************************
 
diff --git a/src/mess/includes/sms.h b/src/mess/includes/sms.h
index 556b663d41a..4f2efcdbbd3 100644
--- a/src/mess/includes/sms.h
+++ b/src/mess/includes/sms.h
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Wilbert Pol, Charles MacDonald,Mathis Rosenhauer,Brad Oliver,Michael Luong,Fabio Priuli,Enik Land
 /*****************************************************************************
  *
diff --git a/src/mess/includes/z80ne.h b/src/mess/includes/z80ne.h
index 6ba7c12831e..b7dbfc9f8c5 100644
--- a/src/mess/includes/z80ne.h
+++ b/src/mess/includes/z80ne.h
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Roberto Lavarone
 /*****************************************************************************
  *
diff --git a/src/mess/machine/mtx.c b/src/mess/machine/mtx.c
index 46f3ec32e3f..0594ec6c086 100644
--- a/src/mess/machine/mtx.c
+++ b/src/mess/machine/mtx.c
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Lee Ward, Dirk Best, Curt Coder
 /*************************************************************************
 
diff --git a/src/mess/machine/sms.c b/src/mess/machine/sms.c
index 5c4d15f2155..89e478c9ba2 100644
--- a/src/mess/machine/sms.c
+++ b/src/mess/machine/sms.c
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Wilbert Pol, Charles MacDonald,Mathis Rosenhauer,Brad Oliver,Michael Luong,Fabio Priuli,Enik Land
 #include "emu.h"
 #include "crsshair.h"
diff --git a/src/mess/machine/z80ne.c b/src/mess/machine/z80ne.c
index 4245165c902..3e5bce4522e 100644
--- a/src/mess/machine/z80ne.c
+++ b/src/mess/machine/z80ne.c
@@ -1,4 +1,4 @@
-// license:???
+// license:BSD-3-Clause
 // copyright-holders:Roberto Lavarone
 /***********************************************************************