diff --git a/library/std/src/sys/sync/condvar/mod.rs b/library/std/src/sys/sync/condvar/mod.rs
index 83cf0ae629851..f7d7c547145c9 100644
--- a/library/std/src/sys/sync/condvar/mod.rs
+++ b/library/std/src/sys/sync/condvar/mod.rs
@@ -1,4 +1,8 @@
 cfg_select! {
+    all(target_os = "emscripten", not(target_feature = "atomics")) => {
+        mod no_threads;
+        pub use no_threads::Condvar;
+    }
     any(
         all(target_os = "windows", not(target_vendor="win7")),
         target_os = "linux",
diff --git a/library/std/src/sys/sync/mutex/mod.rs b/library/std/src/sys/sync/mutex/mod.rs
index e3d6ad1129c83..748811b04ce62 100644
--- a/library/std/src/sys/sync/mutex/mod.rs
+++ b/library/std/src/sys/sync/mutex/mod.rs
@@ -1,4 +1,8 @@
 cfg_select! {
+    all(target_os = "emscripten", not(target_feature = "atomics")) => {
+        mod no_threads;
+        pub use no_threads::Mutex;
+    }
     any(
         all(target_os = "windows", not(target_vendor = "win7")),
         target_os = "linux",
diff --git a/library/std/src/sys/sync/once/mod.rs b/library/std/src/sys/sync/once/mod.rs
index 5796c6d207dba..e94fa5d3610a4 100644
--- a/library/std/src/sys/sync/once/mod.rs
+++ b/library/std/src/sys/sync/once/mod.rs
@@ -8,6 +8,10 @@
 // should help the fast path on call sites.
 
 cfg_select! {
+    all(target_os = "emscripten", not(target_feature = "atomics")) => {
+        mod no_threads;
+        pub use no_threads::{Once, OnceState};
+    }
     any(
         all(target_os = "windows", not(target_vendor="win7")),
         target_os = "linux",
diff --git a/library/std/src/sys/sync/rwlock/mod.rs b/library/std/src/sys/sync/rwlock/mod.rs
index 8603fca2da5b5..a01f210e82d74 100644
--- a/library/std/src/sys/sync/rwlock/mod.rs
+++ b/library/std/src/sys/sync/rwlock/mod.rs
@@ -1,4 +1,8 @@
 cfg_select! {
+    all(target_os = "emscripten", not(target_feature = "atomics")) => {
+        mod no_threads;
+        pub use no_threads::RwLock;
+    }
     any(
         all(target_os = "windows", not(target_vendor = "win7")),
         target_os = "linux",
diff --git a/library/std/src/sys/sync/thread_parking/mod.rs b/library/std/src/sys/sync/thread_parking/mod.rs
index 9d5a0a996b115..75bf63d006d79 100644
--- a/library/std/src/sys/sync/thread_parking/mod.rs
+++ b/library/std/src/sys/sync/thread_parking/mod.rs
@@ -1,4 +1,8 @@
 cfg_select! {
+    all(target_os = "emscripten", not(target_feature = "atomics")) => {
+        mod unsupported;
+        pub use unsupported::Parker;
+    }
     any(
         all(target_os = "windows", not(target_vendor = "win7")),
         target_os = "linux",