diff --git a/fmt/format.h b/fmt/format.h
index 3eb8b1fe..bb3bbfd8 100644
--- a/fmt/format.h
+++ b/fmt/format.h
@@ -381,10 +381,10 @@ template <typename Context>
 class basic_arg;
 
 template <typename Char>
-class ArgFormatter;
+class arg_formatter;
 
 template <typename Char>
-class PrintfArgFormatter;
+class printf_arg_formatter;
 
 template <typename Char>
 class basic_context;
@@ -2016,7 +2016,7 @@ class context_base {
 
 /** The default argument formatter. */
 template <typename Char>
-class ArgFormatter : public internal::ArgFormatterBase<Char> {
+class arg_formatter : public internal::ArgFormatterBase<Char> {
  private:
   basic_context<Char> &ctx_;
 
@@ -2033,8 +2033,8 @@ class ArgFormatter : public internal::ArgFormatterBase<Char> {
     format specifier information for standard argument types.
     \endrst
    */
-  ArgFormatter(basic_buffer<Char> &buffer, basic_context<Char> &ctx,
-               format_specs &spec)
+  arg_formatter(basic_buffer<Char> &buffer, basic_context<Char> &ctx,
+                format_specs &spec)
   : internal::ArgFormatterBase<Char>(buffer, spec), ctx_(ctx) {}
 
   using internal::ArgFormatterBase<Char>::operator();
@@ -2277,7 +2277,7 @@ class basic_writer {
   friend class internal::ArgFormatterBase;
 
   template <typename Char_>
-  friend class PrintfArgFormatter;
+  friend class printf_arg_formatter;
 
  public:
   /**
@@ -2939,11 +2939,11 @@ void vformat_to(basic_buffer<Char> &buffer, BasicCStringRef<Char> format_str,
                 basic_args<Context> args);
 
 inline void vformat_to(buffer &buf, CStringRef format_str, args args) {
-  vformat_to<ArgFormatter<char>>(buf, format_str, args);
+  vformat_to<arg_formatter<char>>(buf, format_str, args);
 }
 
 inline void vformat_to(wbuffer &buf, WCStringRef format_str, wargs args) {
-  vformat_to<ArgFormatter<wchar_t>>(buf, format_str, args);
+  vformat_to<arg_formatter<wchar_t>>(buf, format_str, args);
 }
 
 template <typename... Args>
diff --git a/fmt/ostream.h b/fmt/ostream.h
index f99b9a71..45103734 100644
--- a/fmt/ostream.h
+++ b/fmt/ostream.h
@@ -86,7 +86,7 @@ void format_value(basic_buffer<Char> &buf, const T &value,
   internal::MemoryBuffer<Char, internal::INLINE_BUFFER_SIZE> buffer;
   internal::format_value(buffer, value);
   basic_string_view<Char> str(buffer.data(), buffer.size());
-  do_format_arg< ArgFormatter<Char> >(
+  do_format_arg< arg_formatter<Char> >(
         buf, internal::make_arg< basic_context<Char> >(str), ctx);
 }
 
diff --git a/fmt/printf.h b/fmt/printf.h
index a13684c5..0f3a200a 100644
--- a/fmt/printf.h
+++ b/fmt/printf.h
@@ -210,7 +210,7 @@ class PrintfWidthHandler {
   \endrst
  */
 template <typename Char>
-class PrintfArgFormatter : public internal::ArgFormatterBase<Char> {
+class printf_arg_formatter : public internal::ArgFormatterBase<Char> {
  private:
   void write_null_pointer() {
     this->spec().type_ = 0;
@@ -229,7 +229,7 @@ class PrintfArgFormatter : public internal::ArgFormatterBase<Char> {
     specifier information for standard argument types.
     \endrst
    */
-  PrintfArgFormatter(basic_buffer<Char> &buffer, format_specs &spec)
+  printf_arg_formatter(basic_buffer<Char> &buffer, format_specs &spec)
   : internal::ArgFormatterBase<Char>(buffer, spec) {}
 
   using Base::operator();
@@ -295,7 +295,7 @@ class PrintfArgFormatter : public internal::ArgFormatterBase<Char> {
 
 /** This template formats data and writes the output to a writer. */
 template <typename Char,
-          typename ArgFormatter = PrintfArgFormatter<Char> >
+          typename ArgFormatter = printf_arg_formatter<Char> >
 class printf_context :
   private internal::context_base<
     Char, printf_context<Char, ArgFormatter>> {
diff --git a/test/custom-formatter-test.cc b/test/custom-formatter-test.cc
index 4a582c1a..c4d1f1e8 100644
--- a/test/custom-formatter-test.cc
+++ b/test/custom-formatter-test.cc
@@ -10,38 +10,38 @@
 #include "fmt/printf.h"
 #include "gtest-extra.h"
 
-using fmt::PrintfArgFormatter;
+using fmt::printf_arg_formatter;
 
 // A custom argument formatter that doesn't print `-` for floating-point values
 // rounded to 0.
-class CustomArgFormatter : public fmt::ArgFormatter<char> {
+class CustomArgFormatter : public fmt::arg_formatter<char> {
  public:
   CustomArgFormatter(fmt::buffer &buf, fmt::basic_context<char> &ctx,
                      fmt::format_specs &s)
-  : fmt::ArgFormatter<char>(buf, ctx, s) {}
+  : fmt::arg_formatter<char>(buf, ctx, s) {}
 
-  using fmt::ArgFormatter<char>::operator();
+  using fmt::arg_formatter<char>::operator();
 
   void operator()(double value) {
     if (round(value * pow(10, spec().precision())) == 0)
       value = 0;
-    fmt::ArgFormatter<char>::operator()(value);
+    fmt::arg_formatter<char>::operator()(value);
   }
 };
 
 // A custom argument formatter that doesn't print `-` for floating-point values
 // rounded to 0.
-class CustomPrintfArgFormatter : public PrintfArgFormatter<char> {
+class CustomPrintfArgFormatter : public printf_arg_formatter<char> {
  public:
   CustomPrintfArgFormatter(fmt::buffer &buf, fmt::format_specs &spec)
-  : PrintfArgFormatter<char>(buf, spec) {}
+  : printf_arg_formatter<char>(buf, spec) {}
 
-  using PrintfArgFormatter<char>::operator();
+  using printf_arg_formatter<char>::operator();
 
   void operator()(double value) {
     if (round(value * pow(10, spec().precision())) == 0)
       value = 0;
-    PrintfArgFormatter<char>::operator()(value);
+    printf_arg_formatter<char>::operator()(value);
   }
 };
 
diff --git a/test/ostream-test.cc b/test/ostream-test.cc
index 761820b6..c28635b7 100644
--- a/test/ostream-test.cc
+++ b/test/ostream-test.cc
@@ -58,9 +58,9 @@ TEST(OStreamTest, Enum) {
   EXPECT_EQ("0", fmt::format("{}", A));
 }
 
-struct TestArgFormatter : fmt::ArgFormatter<char> {
+struct TestArgFormatter : fmt::arg_formatter<char> {
   TestArgFormatter(fmt::buffer &buf, fmt::context &ctx, fmt::format_specs &s)
-    : fmt::ArgFormatter<char>(buf, ctx, s) {}
+    : fmt::arg_formatter<char>(buf, ctx, s) {}
 };
 
 TEST(OStreamTest, CustomArg) {