diff --git a/slf4j-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala b/slf4j-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala
index 4c54bd793..686782578 100644
--- a/slf4j-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala
+++ b/slf4j-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala
@@ -16,7 +16,7 @@
 package zio.logging.slf4j.bridge
 
 import org.slf4j.impl.ZioLoggerFactory
-import zio.{ Runtime, ZIO, ZLayer }
+import zio.{ Runtime, Semaphore, Unsafe, ZIO, ZLayer }
 
 object Slf4jBridge {
 
@@ -46,12 +46,15 @@ object Slf4jBridge {
   def initialize(nameAnnotationKey: String): ZLayer[Any, Nothing, Unit] =
     Runtime.enableCurrentFiber ++ layer(nameAnnotationKey)
 
+  private val initLock = Semaphore.unsafe.make(1)(Unsafe.unsafe)
+
   private def layer(nameAnnotationKey: String): ZLayer[Any, Nothing, Unit] =
     ZLayer {
-      ZIO.runtime[Any].flatMap { runtime =>
-        ZIO.succeed {
-          ZioLoggerFactory.initialize(new ZioLoggerRuntime(runtime, nameAnnotationKey))
-        }
-      }
+      for {
+        runtime <- ZIO.runtime[Any]
+        _       <- initLock.withPermit {
+                     ZIO.succeed(ZioLoggerFactory.initialize(new ZioLoggerRuntime(runtime, nameAnnotationKey)))
+                   }
+      } yield ()
     }
 }
diff --git a/slf4j-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala b/slf4j-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala
index ac71f0609..86bcb756e 100644
--- a/slf4j-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala
+++ b/slf4j-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala
@@ -17,6 +17,16 @@ object Slf4jBridgeSpec extends ZIOSpecDefault {
 
   override def spec =
     suite("Slf4jBridge")(
+      test("parallel init") {
+        for {
+          _ <-
+            ZIO.foreachPar((1 to 5).toList) { _ =>
+              ZIO
+                .succeed(org.slf4j.LoggerFactory.getLogger("SLF4J-LOGGER").warn("Test {}!", "WARNING"))
+                .provide(Slf4jBridge.initialize)
+            }
+        } yield assertCompletes
+      },
       test("logs through slf4j - legacy logger name annotation key") {
         val testFailure = new RuntimeException("test error")
         for {
diff --git a/slf4j2-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala b/slf4j2-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala
index 51e455425..716662978 100644
--- a/slf4j2-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala
+++ b/slf4j2-bridge/src/main/scala/zio/logging/slf4j/bridge/Slf4jBridge.scala
@@ -15,7 +15,7 @@
  */
 package zio.logging.slf4j.bridge
 
-import zio.{ Runtime, ZIO, ZLayer }
+import zio.{ Runtime, Semaphore, Unsafe, ZIO, ZLayer }
 
 object Slf4jBridge {
 
@@ -29,15 +29,20 @@ object Slf4jBridge {
    */
   def initializeWithoutFiberRefPropagation: ZLayer[Any, Nothing, Unit] = layer
 
+  private val initLock = Semaphore.unsafe.make(1)(Unsafe.unsafe)
+
   private def layer: ZLayer[Any, Nothing, Unit] =
     ZLayer {
-      ZIO.runtime[Any].flatMap { runtime =>
-        ZIO.succeed {
-          org.slf4j.LoggerFactory
-            .getILoggerFactory()
-            .asInstanceOf[LoggerFactory]
-            .attacheRuntime(new ZioLoggerRuntime(runtime))
-        }
-      }
+      for {
+        runtime <- ZIO.runtime[Any]
+        _       <- initLock.withPermit {
+                     ZIO.succeed(
+                       org.slf4j.LoggerFactory
+                         .getILoggerFactory()
+                         .asInstanceOf[LoggerFactory]
+                         .attacheRuntime(new ZioLoggerRuntime(runtime))
+                     )
+                   }
+      } yield ()
     }
 }
diff --git a/slf4j2-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala b/slf4j2-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala
index 34af42417..c4dd09bbb 100644
--- a/slf4j2-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala
+++ b/slf4j2-bridge/src/test/scala/zio/logging/slf4j/bridge/Slf4jBridgeSpec.scala
@@ -15,6 +15,16 @@ object Slf4jBridgeSpec extends ZIOSpecDefault {
 
   override def spec =
     suite("Slf4jBridge")(
+      test("parallel init") {
+        for {
+          _ <-
+            ZIO.foreachPar((1 to 5).toList) { _ =>
+              ZIO
+                .succeed(org.slf4j.LoggerFactory.getLogger("SLF4J-LOGGER").warn("Test {}!", "WARNING"))
+                .provide(Slf4jBridge.initialize)
+            }
+        } yield assertCompletes
+      },
       test("logs through slf4j") {
         val testFailure = new RuntimeException("test error")
         for {