diff --git a/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryConfiguration.java b/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryConfiguration.java
index 5549c6fe..64a49ebd 100644
--- a/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryConfiguration.java
+++ b/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryConfiguration.java
@@ -63,6 +63,9 @@ public class LibraryConfiguration extends AbstractDescribableImpl<LibraryConfigu
 
     @DataBoundConstructor public LibraryConfiguration(String name, LibraryRetriever retriever) {
         this.name = Util.fixEmptyAndTrim(name);
+        if(this.name == null) {
+            throw new IllegalArgumentException("You must enter a library name");
+        }
         this.retriever = retriever;
     }
 
@@ -70,6 +73,7 @@ public class LibraryConfiguration extends AbstractDescribableImpl<LibraryConfigu
      * Library name.
      * Should match {@link Library#value}, up to the first occurrence of {@code @}, if any.
      */
+    @NonNull
     public String getName() {
         return name;
     }
@@ -173,6 +177,9 @@ public FormValidation doCheckName(@QueryParameter String name) {
 
         @RequirePOST
         public FormValidation doCheckDefaultVersion(@AncestorInPath Item context, @QueryParameter String defaultVersion, @QueryParameter boolean implicit, @QueryParameter boolean allowVersionOverride, @QueryParameter String name) {
+            if (name.isEmpty()) {
+                return FormValidation.error("You must enter a name.");
+            }
             if (defaultVersion.isEmpty()) {
                 if (implicit) {
                     return FormValidation.error("If you load a library implicitly, you must specify a default version.");
diff --git a/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryStep.java b/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryStep.java
index 99dc072a..6cc29bb0 100644
--- a/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryStep.java
+++ b/src/main/java/org/jenkinsci/plugins/workflow/libs/LibraryStep.java
@@ -177,6 +177,9 @@ public static class Execution extends SynchronousNonBlockingStepExecution<Loaded
             TaskListener listener = getContext().get(TaskListener.class);
             String[] parsed = LibraryAdder.parse(step.identifier);
             String name = parsed[0], version = parsed[1];
+            if (name == null) {
+                throw new AbortException("No library name provided");
+            }
             boolean trusted = false;
             Boolean changelog = step.getChangelog();
             LibraryCachingConfiguration cachingConfiguration = null;
@@ -186,7 +189,7 @@ public static class Execution extends SynchronousNonBlockingStepExecution<Loaded
             if (retriever == null) {
                 for (LibraryResolver resolver : ExtensionList.lookup(LibraryResolver.class)) {
                     for (LibraryConfiguration cfg : resolver.forJob(run.getParent(), Collections.singletonMap(name, version))) {
-                        if (cfg.getName().equals(name)) {
+                        if (name.equals(cfg.getName())) {
                             retriever = cfg.getRetriever();
                             trusted = resolver.isTrusted();
                             version = cfg.defaultedVersion(version);
diff --git a/src/main/resources/org/jenkinsci/plugins/workflow/libs/LibraryStep/config.jelly b/src/main/resources/org/jenkinsci/plugins/workflow/libs/LibraryStep/config.jelly
index a1bc8345..799d34aa 100644
--- a/src/main/resources/org/jenkinsci/plugins/workflow/libs/LibraryStep/config.jelly
+++ b/src/main/resources/org/jenkinsci/plugins/workflow/libs/LibraryStep/config.jelly
@@ -26,7 +26,7 @@ THE SOFTWARE.
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form">
     <f:entry field="identifier" title="${%Name and optional version}">
-        <f:textbox/>
+        <f:textbox clazz="required"/>
     </f:entry>
     <f:entry field="changelog" title="${%Include recent changes in jobs}">
         <f:checkbox default="true"/>
diff --git a/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryConfigurationTest.java b/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryConfigurationTest.java
index c91a4627..393485e5 100644
--- a/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryConfigurationTest.java
+++ b/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryConfigurationTest.java
@@ -24,7 +24,7 @@
 
 package org.jenkinsci.plugins.workflow.libs;
 
-import java.util.Collections;
+import java.util.List;
 
 import hudson.plugins.git.GitSCM;
 import org.hamcrest.Matchers;
@@ -69,29 +69,24 @@ public class LibraryConfigurationTest {
     }
 
     @Issue("JENKINS-59527")
-    @Test public void emptyStringDefaultVersionAndName() {
-        String libraryName = "";
-        String defaultVersion = "";
-
-        LibraryConfiguration cfg = new LibraryConfiguration(libraryName, new SCMRetriever(new GitSCM("https://phony.jenkins.io/bar.git")));
-        cfg.setDefaultVersion(defaultVersion);
-
-        assertNull(cfg.getName());
+    @Test public void emptyDefaultVersion() {
+        LibraryConfiguration cfg = new LibraryConfiguration("test", new SCMRetriever(new GitSCM("https://phony.jenkins.io/bar.git")));
+        cfg.setDefaultVersion("");
         assertNull(cfg.getDefaultVersion());
-    }
-
-    @Issue("JENKINS-59527")
-    @Test public void nullDefaultVersionAndName() {
-        String libraryName = null;
-        String defaultVersion = null;
-
-        LibraryConfiguration cfg = new LibraryConfiguration(libraryName, new SCMRetriever(new GitSCM("https://phony.jenkins.io/bar.git")));
-        cfg.setDefaultVersion(defaultVersion);
 
-        assertNull(cfg.getName());
+        cfg = new LibraryConfiguration("test", new SCMRetriever(new GitSCM("https://phony.jenkins.io/bar.git")));
+        cfg.setDefaultVersion(null);
         assertNull(cfg.getDefaultVersion());
     }
 
-
+    @Issue("JENKINS-63355")
+    @Test public void emptyNameCannotBeSaved() throws Exception {
+        assertThrows(IllegalArgumentException.class, () -> GlobalLibraries.get().setLibraries(List.of(
+            new LibraryConfiguration(null, new SCMRetriever(new GitSCM("https://phony.jenkins.io/bar.git")))
+        )));
+        assertThrows(IllegalArgumentException.class, () -> GlobalLibraries.get().setLibraries(List.of(
+            new LibraryConfiguration("", new SCMRetriever(new GitSCM("https://phony.jenkins.io/bar.git")))
+        )));
+    }
 
 }
diff --git a/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryStepTest.java b/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryStepTest.java
index 8e76a469..58bf3120 100644
--- a/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryStepTest.java
+++ b/src/test/java/org/jenkinsci/plugins/workflow/libs/LibraryStepTest.java
@@ -56,6 +56,7 @@
 import org.jvnet.hudson.test.BuildWatcher;
 import org.jvnet.hudson.test.Issue;
 import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.recipes.LocalData;
 
 @Issue("JENKINS-39450")
 public class LibraryStepTest {
@@ -338,4 +339,32 @@ public class LibraryStepTest {
         r.assertLogContains("/lib/java", b);
         r.assertLogContains("/pipeline/java", b);
     }
+
+    @LocalData
+    @Test public void nullNamedLibrary() throws Exception {
+        sampleRepo.init();
+        sampleRepo.write("vars/x.groovy", "def call() {echo 'ran library'}");
+        sampleRepo.git("add", "vars");
+        sampleRepo.git("commit", "--message=init");
+        GlobalLibraries.get().setLibraries(Collections.singletonList(new LibraryConfiguration("stuff", new SCMSourceRetriever(new GitSCMSource(null, sampleRepo.toString(), "", "*", "", true)))));
+
+        /*
+        LibraryConfiguration cfg = new LibraryConfiguration(null, new SCMSourceRetriever(new GitSCMSource(null, sampleRepo.toString(), "", "*", "", true)));
+        cfg.setDefaultVersion("master");
+        cfg.setImplicit(true);
+
+        Folder f = r.jenkins.createProject(Folder.class, "f");
+        f.addProperty(new FolderLibraries(Collections.singletonList(cfg)));
+        f.save();
+         */
+
+        // local data have a folder 'f' with a library with no name (a null name)
+        Folder f = r.jenkins.getItemByFullName("f", Folder.class);
+        assertNotNull(f);
+        WorkflowJob p = f.createProject(WorkflowJob.class, "p");
+        p.setDefinition(new CpsFlowDefinition("library 'stuff@master'; x()", true));
+        WorkflowRun b = r.buildAndAssertSuccess(p);
+        r.assertLogContains("Found a library without name", r.buildAndAssertSuccess(p));
+        r.assertLogContains("ran library", b);
+    }
 }
diff --git a/src/test/resources/org/jenkinsci/plugins/workflow/libs/LibraryStepTest/nullNamedLibrary.zip b/src/test/resources/org/jenkinsci/plugins/workflow/libs/LibraryStepTest/nullNamedLibrary.zip
new file mode 100644
index 00000000..fbb0c7bb
Binary files /dev/null and b/src/test/resources/org/jenkinsci/plugins/workflow/libs/LibraryStepTest/nullNamedLibrary.zip differ