diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 16306146fdc..02d730efc1c 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -225,6 +225,8 @@ Bug Fixes
 
 * SOLR-6613: TextField.analyzeMultiTerm does not throw an exception when Analyzer returns no terms. (Bruno Roustant)
 
+* SOLR-14192: Race condition between SchemaManager and ZkIndexSchemaReader. (ab)
+
 Other Changes
 ---------------------
 
diff --git a/solr/core/src/java/org/apache/solr/schema/ManagedIndexSchemaFactory.java b/solr/core/src/java/org/apache/solr/schema/ManagedIndexSchemaFactory.java
index eb730595684..494e574f96b 100644
--- a/solr/core/src/java/org/apache/solr/schema/ManagedIndexSchemaFactory.java
+++ b/solr/core/src/java/org/apache/solr/schema/ManagedIndexSchemaFactory.java
@@ -35,6 +35,7 @@ import org.apache.solr.core.SolrCore;
 import org.apache.solr.core.SolrResourceLoader;
 import org.apache.solr.util.SystemIdResolver;
 import org.apache.solr.util.plugin.SolrCoreAware;
+import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.data.Stat;
 import org.slf4j.Logger;
@@ -44,7 +45,7 @@ import org.xml.sax.InputSource;
 /** Factory for ManagedIndexSchema */
 public class ManagedIndexSchemaFactory extends IndexSchemaFactory implements SolrCoreAware {
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
-  private static final String UPGRADED_SCHEMA_EXTENSION = ".bak";
+  public static final String UPGRADED_SCHEMA_EXTENSION = ".bak";
   private static final String SCHEMA_DOT_XML = "schema.xml";
 
   public static final String DEFAULT_MANAGED_SCHEMA_RESOURCE_NAME = "managed-schema";
@@ -326,9 +327,19 @@ public class ManagedIndexSchemaFactory extends IndexSchemaFactory implements Sol
     } else {
       // Rename the non-managed schema znode in ZooKeeper
       ZkSolrResourceLoader zkLoader = (ZkSolrResourceLoader)loader;
+      ZkController zkController = zkLoader.getZkController();
+      SolrZkClient zkClient = zkController.getZkClient();
       final String nonManagedSchemaPath = zkLoader.getConfigSetZkPath() + "/" + resourceName;
+      final String lockPath = nonManagedSchemaPath + ".lock";
+      boolean locked = false;
       try {
-        ZkController zkController = zkLoader.getZkController();
+        try {
+          zkClient.makePath(lockPath, null, CreateMode.EPHEMERAL, null, true, true);
+          locked = true;
+        } catch (Exception e) {
+          // some other node already started the upgrade, or an error occurred - bail out
+          return;
+        }
         ZkCmdExecutor zkCmdExecutor = new ZkCmdExecutor(zkController.getClientTimeout());
         if (zkController.pathExists(nonManagedSchemaPath)) {
           // First, copy the non-managed schema znode content to the upgraded schema znode
@@ -360,6 +371,17 @@ public class ManagedIndexSchemaFactory extends IndexSchemaFactory implements Sol
         }
         final String msg = "Error persisting managed schema resource " + managedSchemaResourceName;
         log.warn(msg, e); // Log as warning and suppress the exception
+      } finally {
+        if (locked) {
+          // unlock
+          try {
+            zkClient.delete(lockPath, -1, true);
+          } catch (KeeperException.NoNodeException nne) {
+            // ignore - someone else deleted it
+          } catch (Exception e) {
+            log.warn("Unable to delete schema upgrade lock file " + lockPath, e);
+          }
+        }
       }
     }
   }
diff --git a/solr/core/src/java/org/apache/solr/schema/SchemaManager.java b/solr/core/src/java/org/apache/solr/schema/SchemaManager.java
index 31a7206ed8e..d059543a67f 100644
--- a/solr/core/src/java/org/apache/solr/schema/SchemaManager.java
+++ b/solr/core/src/java/org/apache/solr/schema/SchemaManager.java
@@ -30,6 +30,7 @@ import java.util.concurrent.TimeUnit;
 import org.apache.solr.cloud.ZkController;
 import org.apache.solr.cloud.ZkSolrResourceLoader;
 import org.apache.solr.common.SolrException;
+import org.apache.solr.common.cloud.SolrZkClient;
 import org.apache.solr.common.util.TimeSource;
 import org.apache.solr.core.CoreDescriptor;
 import org.apache.solr.core.SolrCore;
@@ -63,9 +64,17 @@ public class SchemaManager {
 
   final SolrQueryRequest req;
   ManagedIndexSchema managedIndexSchema;
+  int timeout;
 
   public SchemaManager(SolrQueryRequest req){
     this.req = req;
+    //The default timeout is 10 minutes when no BaseSolrResource.UPDATE_TIMEOUT_SECS is specified
+    timeout = req.getParams().getInt(BaseSolrResource.UPDATE_TIMEOUT_SECS, 600);
+
+    //If BaseSolrResource.UPDATE_TIMEOUT_SECS=0 or -1 then end time then we'll try for 10 mins ( default timeout )
+    if (timeout < 1) {
+      timeout = 600;
+    }
   }
 
   /**
@@ -87,13 +96,6 @@ public class SchemaManager {
   }
 
   private List doOperations(List<CommandOperation> operations) throws InterruptedException, IOException, KeeperException {
-    //The default timeout is 10 minutes when no BaseSolrResource.UPDATE_TIMEOUT_SECS is specified
-    int timeout = req.getParams().getInt(BaseSolrResource.UPDATE_TIMEOUT_SECS, 600);
-
-    //If BaseSolrResource.UPDATE_TIMEOUT_SECS=0 or -1 then end time then we'll try for 10 mins ( default timeout )
-    if (timeout < 1) {
-      timeout = 600;
-    }
     TimeOut timeOut = new TimeOut(timeout, TimeUnit.SECONDS, TimeSource.NANO_TIME);
     SolrCore core = req.getCore();
     String errorMsg = "Unable to persist managed schema. ";
@@ -414,12 +416,29 @@ public class SchemaManager {
     return sb.toString();
   }
 
-  public static ManagedIndexSchema getFreshManagedSchema(SolrCore core) throws IOException,
+  private ManagedIndexSchema getFreshManagedSchema(SolrCore core) throws IOException,
       KeeperException, InterruptedException {
 
     SolrResourceLoader resourceLoader = core.getResourceLoader();
     String name = core.getLatestSchema().getResourceName();
     if (resourceLoader instanceof ZkSolrResourceLoader) {
+      SolrZkClient zkClient = ((ZkSolrResourceLoader) resourceLoader).getZkController().getZkClient();
+      try {
+        if (!zkClient.exists(name, true)) {
+          String backupName = name + ManagedIndexSchemaFactory.UPGRADED_SCHEMA_EXTENSION;
+          if (!zkClient.exists(backupName, true)) {
+            log.warn("Unable to retrieve fresh managed schema, neither " + name + " nor " + backupName + " exist.");
+            // use current schema
+            return (ManagedIndexSchema) core.getLatestSchema();
+          } else {
+            name = backupName;
+          }
+        }
+      } catch (Exception e) {
+        log.warn("Unable to retrieve fresh managed schema " + name, e);
+        // use current schema
+        return (ManagedIndexSchema) core.getLatestSchema();
+      }
       InputStream in = resourceLoader.openResource(name);
       if (in instanceof ZkSolrResourceLoader.ZkByteArrayInputStream) {
         int version = ((ZkSolrResourceLoader.ZkByteArrayInputStream) in).getStat().getVersion();