diff --git a/tools/console/client/Makefile b/tools/console/client/Makefile
index e2f2554f92..62d89fdeb9 100644
--- a/tools/console/client/Makefile
+++ b/tools/console/client/Makefile
@@ -1,7 +1,6 @@
 XEN_ROOT=$(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenctrl)
 CFLAGS += $(CFLAGS_libxenstore)
 CFLAGS += -include $(XEN_ROOT)/tools/config.h
diff --git a/tools/console/daemon/Makefile b/tools/console/daemon/Makefile
index 99bb33b6a2..9fc3b6711f 100644
--- a/tools/console/daemon/Makefile
+++ b/tools/console/daemon/Makefile
@@ -1,7 +1,6 @@
 XEN_ROOT=$(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenctrl)
 CFLAGS += $(CFLAGS_libxenstore)
 CFLAGS += $(CFLAGS_libxenevtchn)
diff --git a/tools/debugger/kdd/Makefile b/tools/debugger/kdd/Makefile
index 26116949d4..a72ad3b1e0 100644
--- a/tools/debugger/kdd/Makefile
+++ b/tools/debugger/kdd/Makefile
@@ -1,7 +1,6 @@
 XEN_ROOT = $(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS  += -Werror
 CFLAGS  += $(CFLAGS_libxenctrl)
 CFLAGS  += -DXC_WANT_COMPAT_MAP_FOREIGN_API
 LDLIBS  += $(LDLIBS_libxenctrl)
diff --git a/tools/flask/utils/Makefile b/tools/flask/utils/Makefile
index 6be134142a..88d7edb6b1 100644
--- a/tools/flask/utils/Makefile
+++ b/tools/flask/utils/Makefile
@@ -1,7 +1,6 @@
 XEN_ROOT=$(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenctrl)
 
 TARGETS := flask-loadpolicy flask-setenforce flask-getenforce flask-label-pci flask-get-bool flask-set-bool
diff --git a/tools/fuzz/cpu-policy/Makefile b/tools/fuzz/cpu-policy/Makefile
index 41a2230408..6e7743e0aa 100644
--- a/tools/fuzz/cpu-policy/Makefile
+++ b/tools/fuzz/cpu-policy/Makefile
@@ -17,7 +17,7 @@ install: all
 
 .PHONY: uninstall
 
-CFLAGS += -Werror $(CFLAGS_xeninclude) -D__XEN_TOOLS__
+CFLAGS += $(CFLAGS_xeninclude) -D__XEN_TOOLS__
 CFLAGS += $(APPEND_CFLAGS) -Og
 
 vpath %.c ../../../xen/lib/x86
diff --git a/tools/misc/Makefile b/tools/misc/Makefile
index 0e02401227..1c6e1d6a04 100644
--- a/tools/misc/Makefile
+++ b/tools/misc/Makefile
@@ -1,7 +1,6 @@
 XEN_ROOT=$(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror
 # Include configure output (config.h)
 CFLAGS += -include $(XEN_ROOT)/tools/config.h
 CFLAGS += $(CFLAGS_libxenevtchn)
diff --git a/tools/tests/cpu-policy/Makefile b/tools/tests/cpu-policy/Makefile
index 93af9d76fa..c5b81afc71 100644
--- a/tools/tests/cpu-policy/Makefile
+++ b/tools/tests/cpu-policy/Makefile
@@ -36,7 +36,7 @@ install: all
 uninstall:
 	$(RM) -- $(addprefix $(DESTDIR)$(LIBEXEC_BIN)/,$(TARGETS))
 
-CFLAGS += -Werror -D__XEN_TOOLS__
+CFLAGS += -D__XEN_TOOLS__
 CFLAGS += $(CFLAGS_xeninclude)
 CFLAGS += $(APPEND_CFLAGS)
 
diff --git a/tools/tests/depriv/Makefile b/tools/tests/depriv/Makefile
index 3cba28da25..7d9e3b01bb 100644
--- a/tools/tests/depriv/Makefile
+++ b/tools/tests/depriv/Makefile
@@ -1,7 +1,7 @@
 XEN_ROOT=$(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror -Wno-declaration-after-statement
+CFLAGS += -Wno-declaration-after-statement
 
 CFLAGS += $(CFLAGS_xeninclude)
 CFLAGS += $(CFLAGS_libxenctrl)
diff --git a/tools/tests/resource/Makefile b/tools/tests/resource/Makefile
index b3cd70c06d..a5856bf095 100644
--- a/tools/tests/resource/Makefile
+++ b/tools/tests/resource/Makefile
@@ -27,7 +27,6 @@ install: all
 uninstall:
 	$(RM) -- $(DESTDIR)$(LIBEXEC_BIN)/$(TARGET)
 
-CFLAGS += -Werror
 CFLAGS += $(CFLAGS_xeninclude)
 CFLAGS += $(CFLAGS_libxenctrl)
 CFLAGS += $(CFLAGS_libxenforeginmemory)
diff --git a/tools/tests/tsx/Makefile b/tools/tests/tsx/Makefile
index d7d2a5d95e..a4f516b725 100644
--- a/tools/tests/tsx/Makefile
+++ b/tools/tests/tsx/Makefile
@@ -26,7 +26,6 @@ uninstall:
 .PHONY: uninstall
 uninstall:
 
-CFLAGS += -Werror
 CFLAGS += -I$(XEN_ROOT)/tools/libs/ctrl -I$(XEN_ROOT)/tools/libs/guest
 CFLAGS += $(CFLAGS_xeninclude)
 CFLAGS += $(CFLAGS_libxenctrl)
diff --git a/tools/tests/xenstore/Makefile b/tools/tests/xenstore/Makefile
index 239e1dce47..202dda0d3c 100644
--- a/tools/tests/xenstore/Makefile
+++ b/tools/tests/xenstore/Makefile
@@ -27,7 +27,6 @@ install: all
 uninstall:
 	$(RM) -- $(addprefix $(DESTDIR)$(LIBEXEC_BIN)/,$(TARGETS))
 
-CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenstore)
 CFLAGS += $(APPEND_CFLAGS)
 
diff --git a/tools/xcutils/Makefile b/tools/xcutils/Makefile
index e40a2c4bfa..3687f6cd8f 100644
--- a/tools/xcutils/Makefile
+++ b/tools/xcutils/Makefile
@@ -13,8 +13,6 @@ include $(XEN_ROOT)/tools/Rules.mk
 
 TARGETS := readnotes lsevtchn
 
-CFLAGS += -Werror
-
 CFLAGS_readnotes.o  := $(CFLAGS_libxenevtchn) $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest)
 CFLAGS_lsevtchn.o   := $(CFLAGS_libxenevtchn) $(CFLAGS_libxenctrl)
 
diff --git a/tools/xenmon/Makefile b/tools/xenmon/Makefile
index 3e150b0659..679c4b41a3 100644
--- a/tools/xenmon/Makefile
+++ b/tools/xenmon/Makefile
@@ -13,7 +13,6 @@
 XEN_ROOT=$(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS  += -Werror
 CFLAGS  += $(CFLAGS_libxenevtchn)
 CFLAGS  += $(CFLAGS_libxenctrl)
 LDLIBS  += $(LDLIBS_libxenctrl)
diff --git a/tools/xenpaging/Makefile b/tools/xenpaging/Makefile
index e2ed9eaa3f..835cf2b965 100644
--- a/tools/xenpaging/Makefile
+++ b/tools/xenpaging/Makefile
@@ -12,7 +12,6 @@ OBJS-y   += xenpaging.o
 OBJS-y   += policy_$(POLICY).o
 OBJS-y   += pagein.o
 
-CFLAGS   += -Werror
 CFLAGS   += -Wno-unused
 
 TARGETS := xenpaging
diff --git a/tools/xenpmd/Makefile b/tools/xenpmd/Makefile
index e0d3f06ab2..8da20510b5 100644
--- a/tools/xenpmd/Makefile
+++ b/tools/xenpmd/Makefile
@@ -1,7 +1,6 @@
 XEN_ROOT=$(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenstore)
 
 LDLIBS += $(LDLIBS_libxenstore)
diff --git a/tools/xentop/Makefile b/tools/xentop/Makefile
index 7bd96f34d5..70cc2211c5 100644
--- a/tools/xentop/Makefile
+++ b/tools/xentop/Makefile
@@ -13,7 +13,7 @@
 XEN_ROOT=$(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -DGCC_PRINTF -Werror $(CFLAGS_libxenstat)
+CFLAGS += -DGCC_PRINTF $(CFLAGS_libxenstat)
 LDLIBS += $(LDLIBS_libxenstat) $(CURSES_LIBS) $(TINFO_LIBS) $(SOCKET_LIBS) -lm
 CFLAGS += -DHOST_$(XEN_OS)
 
diff --git a/tools/xentrace/Makefile b/tools/xentrace/Makefile
index 63f2f6532d..d50d400472 100644
--- a/tools/xentrace/Makefile
+++ b/tools/xentrace/Makefile
@@ -1,8 +1,6 @@
 XEN_ROOT=$(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror
-
 CFLAGS += $(CFLAGS_libxenevtchn)
 CFLAGS += $(CFLAGS_libxenctrl)
 LDLIBS += $(LDLIBS_libxenevtchn)
diff --git a/tools/xl/Makefile b/tools/xl/Makefile
index b7f439121a..5f7aa5f46c 100644
--- a/tools/xl/Makefile
+++ b/tools/xl/Makefile
@@ -5,7 +5,7 @@
 XEN_ROOT = $(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Werror -Wno-format-zero-length -Wmissing-declarations \
+CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
 	-Wno-declaration-after-statement -Wformat-nonliteral
 CFLAGS += -fPIC
 
diff --git a/tools/debugger/gdbsx/Rules.mk b/tools/debugger/gdbsx/Rules.mk
index 920f1c87fb..0610db873b 100644
--- a/tools/debugger/gdbsx/Rules.mk
+++ b/tools/debugger/gdbsx/Rules.mk
@@ -1,6 +1,6 @@
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS   += -Werror -Wmissing-prototypes 
+CFLAGS   += -Wmissing-prototypes 
 # (gcc 4.3x and later)   -Wconversion -Wno-sign-conversion
 
 CFLAGS-$(clang) += -Wno-ignored-attributes
diff --git a/tools/firmware/Rules.mk b/tools/firmware/Rules.mk
index 278cca01e4..d3482c9ec4 100644
--- a/tools/firmware/Rules.mk
+++ b/tools/firmware/Rules.mk
@@ -11,8 +11,6 @@ ifneq ($(debug),y)
 CFLAGS += -DNDEBUG
 endif
 
-CFLAGS += -Werror
-
 $(call cc-options-add,CFLAGS,CC,$(EMBEDDED_EXTRA_CFLAGS))
 
 $(call cc-option-add,CFLAGS,CC,-fcf-protection=none)
diff --git a/tools/libfsimage/common.mk b/tools/libfsimage/common.mk
index 77bc957f27..4fc8c66795 100644
--- a/tools/libfsimage/common.mk
+++ b/tools/libfsimage/common.mk
@@ -2,7 +2,7 @@ include $(XEN_ROOT)/tools/Rules.mk
 
 FSDIR := $(libdir)/xenfsimage
 CFLAGS += -Wno-unknown-pragmas -I$(XEN_ROOT)/tools/libfsimage/common/ -DFSIMAGE_FSDIR=\"$(FSDIR)\"
-CFLAGS += -Werror -D_GNU_SOURCE
+CFLAGS += -D_GNU_SOURCE
 LDFLAGS += -L../common/
 
 PIC_OBJS = $(patsubst %.c,%.opic,$(LIB_SRCS-y))
diff --git a/tools/libs/libs.mk b/tools/libs/libs.mk
index 2b8e7a6128..e47fb30ed4 100644
--- a/tools/libs/libs.mk
+++ b/tools/libs/libs.mk
@@ -14,7 +14,7 @@ MINOR ?= 0
 
 SHLIB_LDFLAGS += -Wl,--version-script=libxen$(LIBNAME).map
 
-CFLAGS   += -Werror -Wmissing-prototypes
+CFLAGS   += -Wmissing-prototypes
 CFLAGS   += $(CFLAGS_xeninclude)
 CFLAGS   += $(foreach lib, $(USELIBS_$(LIBNAME)), $(CFLAGS_libxen$(lib)))
 
diff --git a/tools/ocaml/common.make b/tools/ocaml/common.make
index d5478f626f..0c8a597d5b 100644
--- a/tools/ocaml/common.make
+++ b/tools/ocaml/common.make
@@ -9,7 +9,7 @@ OCAMLLEX ?= ocamllex
 OCAMLYACC ?= ocamlyacc
 OCAMLFIND ?= ocamlfind
 
-CFLAGS += -fPIC -Werror -I$(shell ocamlc -where)
+CFLAGS += -fPIC -I$(shell ocamlc -where)
 
 OCAMLOPTFLAG_G := $(shell $(OCAMLOPT) -h 2>&1 | sed -n 's/^  *\(-g\) .*/\1/p')
 OCAMLOPTFLAGS = $(OCAMLOPTFLAG_G) -ccopt "$(LDFLAGS)" -dtypes $(OCAMLINCLUDE) -cc $(CC) -w F -warn-error F
diff --git a/tools/xenstore/Makefile.common b/tools/xenstore/Makefile.common
index 21b78b0538..ddbac052ac 100644
--- a/tools/xenstore/Makefile.common
+++ b/tools/xenstore/Makefile.common
@@ -9,7 +9,6 @@ XENSTORED_OBJS-$(CONFIG_NetBSD) += xenstored_posix.o
 XENSTORED_OBJS-$(CONFIG_FreeBSD) += xenstored_posix.o
 XENSTORED_OBJS-$(CONFIG_MiniOS) += xenstored_minios.o
 
-CFLAGS += -Werror
 # Include configure output (config.h)
 CFLAGS += -include $(XEN_ROOT)/tools/config.h
 CFLAGS += -I./include
