diff --git a/libc/generic/ansi/dir.makefile b/libc/generic/ansi/dir.makefile
index 2c5399d0..0833db63 100644
--- a/libc/generic/ansi/dir.makefile
+++ b/libc/generic/ansi/dir.makefile
@@ -3,10 +3,10 @@ $c_SRCDIR = $(TREE_PATH)/$c/src
 $c_HEADERDIR := $(TREE_PATH)/$c/include
 $c_OBJDIR := $(BUILD_PATH)/$c/obj
 
-$c_HEADERS := assert.h ctype.h errno.h signal.h stdio.h stdlib.h string.h time.h \
+$c_HEADERS := assert.h ctype.h errno.h locale.h signal.h stdio.h stdlib.h string.h time.h \
 	mlibc/ensure.h
 
-$c_OBJECTS := assert.o ctype.o signal.o stdio.o stdlib.o string.o time.o
+$c_OBJECTS := assert.o ctype.o locale.o signal.o stdio.o stdlib.o string.o time.o
 $c_OBJECT_PATHS := $(addprefix $($c_OBJDIR)/,$($c_OBJECTS))
 
 $c_CXX := x86_64-managarm-g++
diff --git a/libc/generic/ansi/include/locale.h b/libc/generic/ansi/include/locale.h
new file mode 100644
index 00000000..57df41d5
--- /dev/null
+++ b/libc/generic/ansi/include/locale.h
@@ -0,0 +1,58 @@
+
+#ifndef _LOCALE_H
+#define _LOCALE_H
+
+#include <mlibc/null.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct lconv {
+	char *decimal_point;
+	char *thousands_sep;
+	char *grouping;
+	char *mon_decimal_point;
+	char *mon_thousands_sep;
+	char *mon_grouping;
+	char *positive_sign;
+	char *negative_sign;
+	char *currency_symbol;
+	char frac_digits;
+	char p_cs_precedes;
+	char n_cs_precedes;
+	char p_sep_by_space;
+	char n_sep_by_space;
+	char p_sign_posn;
+	char n_sign_posn;
+	char *int_curr_symbol;
+	char int_frac_digits;
+	char int_p_cs_precedes;
+	char int_n_cs_precedes;
+	char int_p_sep_by_space;
+	char int_n_sep_by_space;
+	char int_p_sign_posn;
+	char int_n_sign_posn;
+};
+
+#define LC_ALL 1
+#define LC_COLLATE 2
+#define LC_CTYPE 3
+#define LC_MONETARY 4
+#define LC_NUMERIC 5
+#define LC_TIME 6
+
+// [C11/7.11.1] setlocale() function
+
+char *setlocale(int category, const char *locale);
+
+// [C11/7.11.2] Locale inquiry function
+
+struct lconv *localeconv(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _LOCALE_H
+
diff --git a/libc/generic/ansi/src/locale.cpp b/libc/generic/ansi/src/locale.cpp
new file mode 100644
index 00000000..369bf93f
--- /dev/null
+++ b/libc/generic/ansi/src/locale.cpp
@@ -0,0 +1,15 @@
+
+#include <locale.h>
+
+#include <mlibc/ensure.h>
+
+char *setlocale(int category, const char *locale) {
+	__ensure(!"Not implemented");
+	__builtin_unreachable();
+}
+
+struct lconv *localeconv(void) {
+	__ensure(!"Not implemented");
+	__builtin_unreachable();
+}
+