diff --git a/Cargo.lock b/Cargo.lock
index bfa0d5f..36cc203 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -20,6 +20,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -32,6 +38,7 @@ version = "0.14.6"
 dependencies = [
  "clap",
  "heck",
+ "indexmap",
  "log",
  "proc-macro2",
  "quote",
@@ -74,6 +81,12 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
+
 [[package]]
 name = "heck"
 version = "0.3.1"
@@ -92,6 +105,16 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "indexmap"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55e2e4c765aa53a0424761bf9f41aa7a6ac1efa87238f59560640e27fca028f2"
+dependencies = [
+ "autocfg",
+ "hashbrown",
+]
+
 [[package]]
 name = "itoa"
 version = "0.4.6"
diff --git a/Cargo.toml b/Cargo.toml
index 87eb387..069f091 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ travis-ci = { repository = "eqrion/cbindgen" }
 
 [dependencies]
 clap = { version = "2", optional = true }
+indexmap = "1"
 log = "0.4"
 serde = { version = "1.0.103", default-features = false, features = ["derive"]}
 serde_json = "1.0"
diff --git a/docs.md b/docs.md
index cc2176a..4636768 100644
--- a/docs.md
+++ b/docs.md
@@ -683,7 +683,7 @@ swift_name_macro = "CF_SWIFT_NAME"
 # default: "None"
 rename_args = "PascalCase"
 
-# This rule specifies if the order of functions will be sorted in some way.
+# This rule specifies the order in which functions will be sorted.
 #
 # "Name": sort by the name of the function
 # "None": keep order in which the functions have been parsed
@@ -885,6 +885,13 @@ allow_static_const = true
 # default: false
 allow_constexpr = false
 
+# This rule specifies the order in which constants will be sorted.
+#
+# "Name": sort by the name of the constant
+# "None": keep order in which the constants have been parsed
+#
+# default: "Name"
+sort_by = "None"
 
 
 
diff --git a/src/bindgen/config.rs b/src/bindgen/config.rs
index fcbdf9a..a17e207 100644
--- a/src/bindgen/config.rs
+++ b/src/bindgen/config.rs
@@ -255,7 +255,7 @@ impl FromStr for ItemType {
 deserialize_enum_str!(ItemType);
 
 /// Type which specifies the sort order of functions
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub enum SortKey {
     Name,
     None,
@@ -382,8 +382,8 @@ pub struct FunctionConfig {
     pub rename_args: RenameRule,
     /// An optional macro to use when generating Swift function name attributes
     pub swift_name_macro: Option<String>,
-    /// Sort key for function names
-    pub sort_by: SortKey,
+    /// Sort key for functions
+    pub sort_by: Option<SortKey>,
     /// Optional text to output after functions which return `!`.
     pub no_return: Option<String>,
 }
@@ -397,7 +397,7 @@ impl Default for FunctionConfig {
             args: Layout::Auto,
             rename_args: RenameRule::None,
             swift_name_macro: None,
-            sort_by: SortKey::Name,
+            sort_by: None,
             no_return: None,
         }
     }
@@ -644,6 +644,8 @@ pub struct ConstantConfig {
     pub allow_static_const: bool,
     /// Whether a generated constant should be constexpr in C++ mode.
     pub allow_constexpr: bool,
+    /// Sort key for constants
+    pub sort_by: Option<SortKey>,
 }
 
 impl Default for ConstantConfig {
@@ -651,6 +653,7 @@ impl Default for ConstantConfig {
         ConstantConfig {
             allow_static_const: true,
             allow_constexpr: false,
+            sort_by: None,
         }
     }
 }
@@ -835,6 +838,8 @@ pub struct Config {
     pub cpp_compat: bool,
     /// The style to declare structs, enums and unions in for C
     pub style: Style,
+    /// Default sort key for functions and constants.
+    pub sort_by: SortKey,
     /// The configuration options for parsing
     pub parse: ParseConfig,
     /// The configuration options for exporting
@@ -889,6 +894,7 @@ impl Default for Config {
             language: Language::Cxx,
             cpp_compat: false,
             style: Style::Type,
+            sort_by: SortKey::Name,
             macro_expansion: Default::default(),
             parse: ParseConfig::default(),
             export: ExportConfig::default(),
diff --git a/src/bindgen/ir/item.rs b/src/bindgen/ir/item.rs
index 73915a6..57ac7fc 100644
--- a/src/bindgen/ir/item.rs
+++ b/src/bindgen/ir/item.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use std::collections::BTreeMap;
+use indexmap::IndexMap;
 use std::mem;
 
 use crate::bindgen::config::Config;
@@ -75,13 +75,13 @@ pub enum ItemValue<T: Item> {
 
 #[derive(Debug, Clone)]
 pub struct ItemMap<T: Item> {
-    data: BTreeMap<Path, ItemValue<T>>,
+    data: IndexMap<Path, ItemValue<T>>,
 }
 
 impl<T: Item + Clone> ItemMap<T> {
     pub fn default() -> ItemMap<T> {
         ItemMap {
-            data: BTreeMap::new(),
+            data: Default::default(),
         }
     }
 
@@ -150,7 +150,7 @@ impl<T: Item + Clone> ItemMap<T> {
     where
         F: Fn(&T) -> bool,
     {
-        let data = mem::replace(&mut self.data, BTreeMap::new());
+        let data = mem::replace(&mut self.data, Default::default());
 
         for (name, container) in data {
             match container {
diff --git a/src/bindgen/library.rs b/src/bindgen/library.rs
index fdd6e17..fc0c44d 100644
--- a/src/bindgen/library.rs
+++ b/src/bindgen/library.rs
@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use std::collections::HashMap;
-use std::mem;
 
 use crate::bindgen::bindings::Bindings;
 use crate::bindgen::config::{Config, Language, SortKey};
@@ -58,10 +57,8 @@ impl Library {
         self.transfer_annotations();
         self.simplify_standard_types();
 
-        match self.config.function.sort_by {
-            SortKey::Name => {
-                self.functions.sort_by(|x, y| x.path.cmp(&y.path));
-            }
+        match self.config.function.sort_by.unwrap_or(self.config.sort_by) {
+            SortKey::Name => self.functions.sort_by(|x, y| x.path.cmp(&y.path)),
             SortKey::None => { /* keep input order */ }
         }
 
@@ -104,18 +101,28 @@ impl Library {
 
         let items = dependencies.order;
         let constants = if self.config.export.should_generate(ItemType::Constants) {
-            self.constants.to_vec()
+            let mut constants = self.constants.to_vec();
+            match self.config.constant.sort_by.unwrap_or(self.config.sort_by) {
+                SortKey::Name => constants.sort_by(|x, y| x.path.cmp(&y.path)),
+                SortKey::None => { /* keep input order */ }
+            }
+            constants
         } else {
             vec![]
         };
 
         let globals = if self.config.export.should_generate(ItemType::Globals) {
-            self.globals.to_vec()
+            let mut globals = self.globals.to_vec();
+            match self.config.constant.sort_by.unwrap_or(self.config.sort_by) {
+                SortKey::Name => globals.sort_by(|x, y| x.path.cmp(&y.path)),
+                SortKey::None => { /* keep input order */ }
+            }
+            globals
         } else {
             vec![]
         };
         let functions = if self.config.export.should_generate(ItemType::Functions) {
-            mem::replace(&mut self.functions, vec![])
+            self.functions
         } else {
             vec![]
         };
diff --git a/template.toml b/template.toml
index 0e515fd..e997f2d 100644
--- a/template.toml
+++ b/template.toml
@@ -43,6 +43,7 @@ line-endings = "LF" # also "CR", "CRLF", "Native"
 ############################# Codegen Options ##################################
 
 style = "both"
+sort_by = "Name" # default for `fn.sort_by` and `const.sort_by`
 
 
 
@@ -117,6 +118,7 @@ private_default_tagged_enum_constructor = false
 [const]
 allow_static_const = true
 allow_constexpr = false
+sort_by = "Name"
 
 
 
@@ -145,8 +147,3 @@ crates = []
 all_features = false
 default_features = true
 features = []
-
-
-
-
-
diff --git a/tests/expectations/both/constant_sort_name.c b/tests/expectations/both/constant_sort_name.c
new file mode 100644
index 0000000..0ae1d49
--- /dev/null
+++ b/tests/expectations/both/constant_sort_name.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define A 0
+
+#define B 0
+
+extern const uint8_t C;
+
+extern const uint8_t D;
diff --git a/tests/expectations/both/constant_sort_name.compat.c b/tests/expectations/both/constant_sort_name.compat.c
new file mode 100644
index 0000000..1b9032a
--- /dev/null
+++ b/tests/expectations/both/constant_sort_name.compat.c
@@ -0,0 +1,20 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define A 0
+
+#define B 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+extern const uint8_t C;
+
+extern const uint8_t D;
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
diff --git a/tests/expectations/both/constant_sort_none.c b/tests/expectations/both/constant_sort_none.c
new file mode 100644
index 0000000..2ec6a14
--- /dev/null
+++ b/tests/expectations/both/constant_sort_none.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define B 0
+
+#define A 0
+
+extern const uint8_t D;
+
+extern const uint8_t C;
diff --git a/tests/expectations/both/constant_sort_none.compat.c b/tests/expectations/both/constant_sort_none.compat.c
new file mode 100644
index 0000000..c9c7445
--- /dev/null
+++ b/tests/expectations/both/constant_sort_none.compat.c
@@ -0,0 +1,20 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define B 0
+
+#define A 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+extern const uint8_t D;
+
+extern const uint8_t C;
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
diff --git a/tests/expectations/constant_sort_name.c b/tests/expectations/constant_sort_name.c
new file mode 100644
index 0000000..0ae1d49
--- /dev/null
+++ b/tests/expectations/constant_sort_name.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define A 0
+
+#define B 0
+
+extern const uint8_t C;
+
+extern const uint8_t D;
diff --git a/tests/expectations/constant_sort_name.compat.c b/tests/expectations/constant_sort_name.compat.c
new file mode 100644
index 0000000..1b9032a
--- /dev/null
+++ b/tests/expectations/constant_sort_name.compat.c
@@ -0,0 +1,20 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define A 0
+
+#define B 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+extern const uint8_t C;
+
+extern const uint8_t D;
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
diff --git a/tests/expectations/constant_sort_name.cpp b/tests/expectations/constant_sort_name.cpp
new file mode 100644
index 0000000..6de3dda
--- /dev/null
+++ b/tests/expectations/constant_sort_name.cpp
@@ -0,0 +1,17 @@
+#include <cstdarg>
+#include <cstdint>
+#include <cstdlib>
+#include <ostream>
+#include <new>
+
+static const uint8_t A = 0;
+
+static const uint8_t B = 0;
+
+extern "C" {
+
+extern const uint8_t C;
+
+extern const uint8_t D;
+
+} // extern "C"
diff --git a/tests/expectations/constant_sort_none.c b/tests/expectations/constant_sort_none.c
new file mode 100644
index 0000000..2ec6a14
--- /dev/null
+++ b/tests/expectations/constant_sort_none.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define B 0
+
+#define A 0
+
+extern const uint8_t D;
+
+extern const uint8_t C;
diff --git a/tests/expectations/constant_sort_none.compat.c b/tests/expectations/constant_sort_none.compat.c
new file mode 100644
index 0000000..c9c7445
--- /dev/null
+++ b/tests/expectations/constant_sort_none.compat.c
@@ -0,0 +1,20 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define B 0
+
+#define A 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+extern const uint8_t D;
+
+extern const uint8_t C;
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
diff --git a/tests/expectations/constant_sort_none.cpp b/tests/expectations/constant_sort_none.cpp
new file mode 100644
index 0000000..6e7360b
--- /dev/null
+++ b/tests/expectations/constant_sort_none.cpp
@@ -0,0 +1,17 @@
+#include <cstdarg>
+#include <cstdint>
+#include <cstdlib>
+#include <ostream>
+#include <new>
+
+static const uint8_t B = 0;
+
+static const uint8_t A = 0;
+
+extern "C" {
+
+extern const uint8_t D;
+
+extern const uint8_t C;
+
+} // extern "C"
diff --git a/tests/expectations/tag/constant_sort_name.c b/tests/expectations/tag/constant_sort_name.c
new file mode 100644
index 0000000..0ae1d49
--- /dev/null
+++ b/tests/expectations/tag/constant_sort_name.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define A 0
+
+#define B 0
+
+extern const uint8_t C;
+
+extern const uint8_t D;
diff --git a/tests/expectations/tag/constant_sort_name.compat.c b/tests/expectations/tag/constant_sort_name.compat.c
new file mode 100644
index 0000000..1b9032a
--- /dev/null
+++ b/tests/expectations/tag/constant_sort_name.compat.c
@@ -0,0 +1,20 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define A 0
+
+#define B 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+extern const uint8_t C;
+
+extern const uint8_t D;
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
diff --git a/tests/expectations/tag/constant_sort_none.c b/tests/expectations/tag/constant_sort_none.c
new file mode 100644
index 0000000..2ec6a14
--- /dev/null
+++ b/tests/expectations/tag/constant_sort_none.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define B 0
+
+#define A 0
+
+extern const uint8_t D;
+
+extern const uint8_t C;
diff --git a/tests/expectations/tag/constant_sort_none.compat.c b/tests/expectations/tag/constant_sort_none.compat.c
new file mode 100644
index 0000000..c9c7445
--- /dev/null
+++ b/tests/expectations/tag/constant_sort_none.compat.c
@@ -0,0 +1,20 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define B 0
+
+#define A 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+extern const uint8_t D;
+
+extern const uint8_t C;
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
diff --git a/tests/rust/constant_sort_name.rs b/tests/rust/constant_sort_name.rs
new file mode 100644
index 0000000..96c1185
--- /dev/null
+++ b/tests/rust/constant_sort_name.rs
@@ -0,0 +1,7 @@
+pub const B: u8 = 0;
+pub const A: u8 = 0;
+
+#[no_mangle]
+pub static D: u8 = 0;
+#[no_mangle]
+pub static C: u8 = 0;
diff --git a/tests/rust/constant_sort_none.rs b/tests/rust/constant_sort_none.rs
new file mode 100644
index 0000000..96c1185
--- /dev/null
+++ b/tests/rust/constant_sort_none.rs
@@ -0,0 +1,7 @@
+pub const B: u8 = 0;
+pub const A: u8 = 0;
+
+#[no_mangle]
+pub static D: u8 = 0;
+#[no_mangle]
+pub static C: u8 = 0;
diff --git a/tests/rust/constant_sort_none.toml b/tests/rust/constant_sort_none.toml
new file mode 100644
index 0000000..182d0d4
--- /dev/null
+++ b/tests/rust/constant_sort_none.toml
@@ -0,0 +1,2 @@
+[const]
+sort_by = "None"