diff --git a/mlua-sys/Cargo.toml b/mlua-sys/Cargo.toml
index 6bdcbe6..a88019b 100644
--- a/mlua-sys/Cargo.toml
+++ b/mlua-sys/Cargo.toml
@@ -40,7 +40,7 @@ cfg-if = "1.0"
 pkg-config = "0.3.17"
 lua-src = { version = ">= 547.0.0, < 547.1.0", optional = true }
 luajit-src = { version = ">= 210.5.0, < 210.6.0", optional = true }
-luau0-src = { git = "https://github.com/mlua-rs/luau-src-rs", optional = true }
+luau0-src = { git = "https://github.com/mlua-rs/luau-src-rs", rev = "f89e9f2", optional = true }
 
 [lints.rust]
 unexpected_cfgs = { level = "allow", check-cfg = ['cfg(raw_dylib)'] }
diff --git a/mlua-sys/src/luau/luarequire.rs b/mlua-sys/src/luau/luarequire.rs
new file mode 100644
index 0000000..d372610
--- /dev/null
+++ b/mlua-sys/src/luau/luarequire.rs
@@ -0,0 +1,125 @@
+//! Contains definitions from `Require.h`.
+
+use std::os::raw::{c_char, c_int, c_void};
+
+use super::lua::lua_State;
+
+#[repr(C)]
+pub enum luarequire_NavigateResult {
+    Success,
+    Ambiguous,
+    NotFound,
+}
+
+// Functions returning WriteSuccess are expected to set their size_out argument
+// to the number of bytes written to the buffer. If WriteBufferTooSmall is
+// returned, size_out should be set to the required buffer size.
+#[repr(C)]
+pub enum luarequire_WriteResult {
+    Success,
+    BufferTooSmall,
+    Failure,
+}
+
+#[repr(C)]
+pub struct luarequire_Configuration {
+    // Returns whether requires are permitted from the given chunkname.
+    pub is_require_allowed:
+        unsafe extern "C" fn(L: *mut lua_State, ctx: *mut c_void, requirer_chunkname: *const c_char) -> bool,
+
+    // Resets the internal state to point at the requirer module.
+    pub reset: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        requirer_chunkname: *const c_char,
+    ) -> luarequire_NavigateResult,
+
+    // Resets the internal state to point at an aliased module, given its exact path from a configuration
+    // file. This function is only called when an alias's path cannot be resolved relative to its
+    // configuration file.
+    pub jump_to_alias: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        path: *const c_char,
+    ) -> luarequire_NavigateResult,
+
+    // Navigates through the context by making mutations to the internal state.
+    pub to_parent: unsafe extern "C" fn(L: *mut lua_State, ctx: *mut c_void) -> luarequire_NavigateResult,
+    pub to_child: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        name: *const c_char,
+    ) -> luarequire_NavigateResult,
+
+    // Returns whether the context is currently pointing at a module.
+    pub is_module_present: unsafe extern "C" fn(L: *mut lua_State, ctx: *mut c_void) -> bool,
+
+    // Provides the contents of the current module. This function is only called if is_module_present returns
+    // true.
+    pub get_contents: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        buffer: *mut c_char,
+        buffer_size: usize,
+        size_out: *mut usize,
+    ) -> luarequire_WriteResult,
+
+    // Provides a chunkname for the current module. This will be accessible through the debug library. This
+    // function is only called if is_module_present returns true.
+    pub get_chunkname: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        buffer: *mut c_char,
+        buffer_size: usize,
+        size_out: *mut usize,
+    ) -> luarequire_WriteResult,
+
+    // Provides a cache key representing the current module. This function is only called if
+    // is_module_present returns true.
+    pub get_cache_key: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        buffer: *mut c_char,
+        buffer_size: usize,
+        size_out: *mut usize,
+    ) -> luarequire_WriteResult,
+
+    // Returns whether a configuration file is present in the current context.
+    // If not, require-by-string will call to_parent until either a configuration file is present or
+    // NAVIGATE_FAILURE is returned (at root).
+    pub is_config_present: unsafe extern "C" fn(L: *mut lua_State, ctx: *mut c_void) -> bool,
+
+    // Provides the contents of the configuration file in the current context.
+    // This function is only called if is_config_present returns true.
+    pub get_config: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        buffer: *mut c_char,
+        buffer_size: usize,
+        size_out: *mut usize,
+    ) -> luarequire_WriteResult,
+
+    // Executes the module and places the result on the stack. Returns the number of results placed on the
+    // stack.
+    pub load: unsafe extern "C" fn(
+        L: *mut lua_State,
+        ctx: *mut c_void,
+        chunkname: *const c_char,
+        contents: *const c_char,
+    ) -> c_int,
+}
+
+// Populates function pointers in the given luarequire_Configuration.
+pub type luarequire_Configuration_init = unsafe extern "C" fn(config: *mut luarequire_Configuration);
+
+extern "C-unwind" {
+    // Initializes and pushes the require closure onto the stack without registration.
+    pub fn lua_pushrequire(
+        L: *mut lua_State,
+        config_init: luarequire_Configuration_init,
+        ctx: *mut c_void,
+    ) -> c_int;
+
+    // Initializes the require library and registers it globally.
+    pub fn luaopen_require(L: *mut lua_State, config_init: luarequire_Configuration_init, ctx: *mut c_void);
+}
diff --git a/mlua-sys/src/luau/mod.rs b/mlua-sys/src/luau/mod.rs
index b36fee5..ea882a9 100644
--- a/mlua-sys/src/luau/mod.rs
+++ b/mlua-sys/src/luau/mod.rs
@@ -6,6 +6,7 @@ pub use lua::*;
 pub use luacode::*;
 pub use luacodegen::*;
 pub use lualib::*;
+pub use luarequire::*;
 
 pub mod compat;
 pub mod lauxlib;
@@ -13,3 +14,4 @@ pub mod lua;
 pub mod luacode;
 pub mod luacodegen;
 pub mod lualib;
+pub mod luarequire;