diff --git a/libc/bionic/ifaddrs.cpp b/libc/bionic/ifaddrs.cpp
index 408949c..f5b080c 100644
--- a/libc/bionic/ifaddrs.cpp
+++ b/libc/bionic/ifaddrs.cpp
@@ -59,7 +59,7 @@
   sockaddr_storage ifa_ifu;
   char name[IFNAMSIZ + 1];
 
-  ifaddrs_storage(ifaddrs** list) {
+  explicit ifaddrs_storage(ifaddrs** list) {
     memset(this, 0, sizeof(*this));
 
     // push_front onto `list`.
diff --git a/libc/bionic/libc_logging.cpp b/libc/bionic/libc_logging.cpp
index 6802944..517d047 100644
--- a/libc/bionic/libc_logging.cpp
+++ b/libc/bionic/libc_logging.cpp
@@ -107,7 +107,7 @@
 
 struct FdOutputStream {
  public:
-  FdOutputStream(int fd) : total(0), fd_(fd) {
+  explicit FdOutputStream(int fd) : total(0), fd_(fd) {
   }
 
   void Send(const char* data, int len) {
diff --git a/libc/bionic/locale.cpp b/libc/bionic/locale.cpp
index b42b440..f26a5f2 100644
--- a/libc/bionic/locale.cpp
+++ b/libc/bionic/locale.cpp
@@ -44,10 +44,10 @@
 struct __locale_t {
   size_t mb_cur_max;
 
-  __locale_t(size_t mb_cur_max) : mb_cur_max(mb_cur_max) {
+  explicit __locale_t(size_t mb_cur_max) : mb_cur_max(mb_cur_max) {
   }
 
-  __locale_t(const __locale_t* other) {
+  explicit __locale_t(const __locale_t* other) {
     if (other == LC_GLOBAL_LOCALE) {
       mb_cur_max = __bionic_current_locale_is_utf8 ? 4 : 1;
     } else {
diff --git a/libc/bionic/net_if.cpp b/libc/bionic/net_if.cpp
index f8d73bd..db9c9ea2 100644
--- a/libc/bionic/net_if.cpp
+++ b/libc/bionic/net_if.cpp
@@ -77,7 +77,7 @@
   if_list* next;
   struct if_nameindex data;
 
-  if_list(if_list** list) {
+  explicit if_list(if_list** list) {
     // push_front onto `list`.
     next = *list;
     *list = this;
diff --git a/libc/bionic/system_properties.cpp b/libc/bionic/system_properties.cpp
index 9c992da..0f68431 100644
--- a/libc/bionic/system_properties.cpp
+++ b/libc/bionic/system_properties.cpp
@@ -192,7 +192,7 @@
     const uint32_t n;
     const prop_info *pi;
 
-    find_nth_cookie(uint32_t n) : count(0), n(n), pi(NULL) {
+    explicit find_nth_cookie(uint32_t n) : count(0), n(n), pi(NULL) {
     }
 };
 
diff --git a/libc/malloc_debug/Config.cpp b/libc/malloc_debug/Config.cpp
index cc60086..6220a23 100644
--- a/libc/malloc_debug/Config.cpp
+++ b/libc/malloc_debug/Config.cpp
@@ -84,7 +84,7 @@
 
 class PropertyParser {
  public:
-  PropertyParser(const char* property) : cur_(property) {}
+  explicit PropertyParser(const char* property) : cur_(property) {}
 
   bool Get(std::string* property, size_t* value, bool* value_set);
 
diff --git a/libc/stdio/stdio.cpp b/libc/stdio/stdio.cpp
index 1c31a27..5df1bb9 100644
--- a/libc/stdio/stdio.cpp
+++ b/libc/stdio/stdio.cpp
@@ -90,7 +90,7 @@
 
 class ScopedFileLock {
  public:
-  ScopedFileLock(FILE* fp) : fp_(fp) {
+  explicit ScopedFileLock(FILE* fp) : fp_(fp) {
     FLOCKFILE(fp_);
   }
   ~ScopedFileLock() {