diff --git a/src/Plugin/migrate/process/ParseEntityLookup.php b/src/Plugin/migrate/process/ParseEntityLookup.php
index 98a8eec..b148230 100644
--- a/src/Plugin/migrate/process/ParseEntityLookup.php
+++ b/src/Plugin/migrate/process/ParseEntityLookup.php
@@ -135,6 +135,10 @@ public static function create(ContainerInterface $container, array $configuratio
     }
 
     public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+        if ($value == NULL || trim($value) == "") {
+            return NULL;
+        }
+
         $delimiter = $this->configuration['delimiter'] ?: self::default_delimiter;
 
         // split the source value into fields using the defined delimiter
diff --git a/tests/Plugin/migrate/process/ParseEntityLookupTest.php b/tests/Plugin/migrate/process/ParseEntityLookupTest.php
index 130b4ff..939bcfa 100644
--- a/tests/Plugin/migrate/process/ParseEntityLookupTest.php
+++ b/tests/Plugin/migrate/process/ParseEntityLookupTest.php
@@ -352,6 +352,9 @@ public function testTransformOk() {
         self::assertTrue($transformInvoked);
     }
 
+    /**
+     * Improper formatting of the source value should result in a MigrateException
+     */
     public function testTransformInvalidSourceValueTooSmall() {
         // The source value from the spreadsheet in the form:
         //   <entity type>:<bundle>:<value_key>:<value>
@@ -368,6 +371,9 @@ public function testTransformInvalidSourceValueTooSmall() {
         }
     }
 
+    /**
+     * Improper formatting of the source value should result in a MigrateException
+     */
     public function testTransformInvalidSourceValueTooBig() {
         // The source value from the spreadsheet in the form:
         //   <entity type>:<bundle>:<value_key>:<value>
@@ -384,6 +390,9 @@ public function testTransformInvalidSourceValueTooBig() {
         }
     }
 
+    /**
+     * Improper formatting of the source value should result in a MigrateException
+     */
     public function testTransformInvalidSourceValueEmptyLastElement() {
         // The source value from the spreadsheet in the form:
         //   <entity type>:<bundle>:<value_key>:<value>
@@ -399,4 +408,30 @@ public function testTransformInvalidSourceValueEmptyLastElement() {
         }
     }
 
+    /**
+     * Empty source values should result in NULL being returned.
+     */
+    public function testEmptyValue() {
+        $source_value = " ";
+        $result = $this->underTest->transform($source_value, $this->mockMigrationExe, new Row(), "foo");
+        self::assertNull($result);
+    }
+
+    /**
+     * Zero-length source values should result in NULL being returned.
+     */
+    public function testZeroLengthValue() {
+        $source_value = "";
+        $result = $this->underTest->transform($source_value, $this->mockMigrationExe, new Row(), "foo");
+        self::assertNull($result);
+    }
+
+    /**
+     * NULL source values should result in NULL being returned.
+     */
+    public function testNullValue() {
+        $source_value = NULL;
+        $result = $this->underTest->transform($source_value, $this->mockMigrationExe, new Row(), "foo");
+        self::assertNull($result);
+    }
 }
\ No newline at end of file