diff --git a/Cargo.toml b/Cargo.toml
index 1367a05..e257b49 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,6 +25,8 @@ optional = true
 build-bindgen = ["bindgen"]
 # enable DRED
 dred = []
+# enable OSCE
+osce = []
 # disable run-time checks that are cheap and safe for use in production.
 no-hardening = []
 # disable stack protection.
diff --git a/build.rs b/build.rs
index 91b5aab..e0860ee 100644
--- a/build.rs
+++ b/build.rs
@@ -99,6 +99,9 @@ fn build() {
     if cfg!(feature = "dred") {
         cmake.define("OPUS_DRED", "ON");
     }
+    if cfg!(feature = "osce") {
+        cmake.define("OPUS_OSCE", "ON");
+    }
     if cfg!(feature = "no-hardening") {
         cmake.define("OPUS_HARDENING", "OFF");
     }