diff --git a/connect/api/src/main/java/org/apache/kafka/connect/data/SchemaProjector.java b/connect/api/src/main/java/org/apache/kafka/connect/data/SchemaProjector.java
index ad0caf85f83..6277e44c4e0 100644
--- a/connect/api/src/main/java/org/apache/kafka/connect/data/SchemaProjector.java
+++ b/connect/api/src/main/java/org/apache/kafka/connect/data/SchemaProjector.java
@@ -111,14 +111,12 @@ public class SchemaProjector {
                 } catch (SchemaProjectorException e) {
                     throw new SchemaProjectorException("Error projecting " + sourceField.name(), e);
                 }
+            } else if (targetField.schema().isOptional()) {
+                // Ignore missing field
+            } else if (targetField.schema().defaultValue() != null) {
+                targetStruct.put(fieldName, targetField.schema().defaultValue());
             } else {
-                Object targetDefault;
-                if (targetField.schema().defaultValue() != null) {
-                    targetDefault = targetField.schema().defaultValue();
-                } else {
-                    throw new SchemaProjectorException("Cannot project " + source.schema() + " to " + target.schema());
-                }
-                targetStruct.put(fieldName, targetDefault);
+                throw new SchemaProjectorException("Required field `" +  fieldName + "` is missing from source schema: " + source);
             }
         }
         return targetStruct;
diff --git a/connect/api/src/test/java/org/apache/kafka/connect/data/SchemaProjectorTest.java b/connect/api/src/test/java/org/apache/kafka/connect/data/SchemaProjectorTest.java
index 0b1760be7a2..101be043226 100644
--- a/connect/api/src/test/java/org/apache/kafka/connect/data/SchemaProjectorTest.java
+++ b/connect/api/src/test/java/org/apache/kafka/connect/data/SchemaProjectorTest.java
@@ -469,6 +469,27 @@ public class SchemaProjectorTest {
         }
     }
 
+    @Test
+    public void testProjectMissingDefaultValuedStructField() {
+        final Schema source = SchemaBuilder.struct().build();
+        final Schema target = SchemaBuilder.struct().field("id", SchemaBuilder.int64().defaultValue(42L).build()).build();
+        assertEquals(42L, (long) ((Struct) SchemaProjector.project(source, new Struct(source), target)).getInt64("id"));
+    }
+
+    @Test
+    public void testProjectMissingOptionalStructField() {
+        final Schema source = SchemaBuilder.struct().build();
+        final Schema target = SchemaBuilder.struct().field("id", SchemaBuilder.OPTIONAL_INT64_SCHEMA).build();
+        assertEquals(null, ((Struct) SchemaProjector.project(source, new Struct(source), target)).getInt64("id"));
+    }
+
+    @Test(expected = SchemaProjectorException.class)
+    public void testProjectMissingRequiredField() {
+        final Schema source = SchemaBuilder.struct().build();
+        final Schema target = SchemaBuilder.struct().field("id", SchemaBuilder.INT64_SCHEMA).build();
+        SchemaProjector.project(source, new Struct(source), target);
+    }
+
     private void verifyOptionalProjection(Schema source, Type targetType, Object value, Object defaultValue, Object expectedProjected, boolean optional) {
         Schema target;
         assert source.isOptional();