diff --git a/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidator.java b/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidator.java
index e18cb182..7c253031 100644
--- a/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidator.java
+++ b/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidator.java
@@ -438,10 +438,13 @@ public class QInstanceValidator
                for(QFieldSection section : table.getSections())
                {
                   validateTableSection(qInstance, table, section, fieldNamesInSections);
-                  if(section.getTier().equals(Tier.T1))
+                  if(assertCondition(section.getTier() != null, "Table " + tableName + " " + section.getName() + " is missing its tier"))
                   {
-                     assertCondition(tier1Section == null, "Table " + tableName + " has more than 1 section listed as Tier 1");
-                     tier1Section = section;
+                     if(section.getTier().equals(Tier.T1))
+                     {
+                        assertCondition(tier1Section == null, "Table " + tableName + " has more than 1 section listed as Tier 1");
+                        tier1Section = section;
+                     }
                   }
 
                   assertCondition(!usedSectionNames.contains(section.getName()), "Table " + tableName + " has more than 1 section named " + section.getName());
@@ -1099,13 +1102,34 @@ public class QInstanceValidator
       boolean hasFields = CollectionUtils.nullSafeHasContents(section.getFieldNames());
       boolean hasWidget = StringUtils.hasContent(section.getWidgetName());
 
-      if(assertCondition(hasFields || hasWidget, "Table " + table.getName() + " section " + section.getName() + " does not have any fields or a widget."))
+      String sectionPrefix = "Table " + table.getName() + " section " + section.getName() + " ";
+      if(assertCondition(hasFields || hasWidget, sectionPrefix + "does not have any fields or a widget."))
       {
          if(table.getFields() != null && hasFields)
          {
             for(String fieldName : section.getFieldNames())
             {
-               assertCondition(table.getFields().containsKey(fieldName), "Table " + table.getName() + " section " + section.getName() + " specifies fieldName " + fieldName + ", which is not a field on this table.");
+               if(fieldName.contains("."))
+               {
+                  String[] parts            = fieldName.split("\\.");
+                  String   otherTableName   = parts[0];
+                  String   foreignFieldName = parts[1];
+
+                  if(assertCondition(qInstance.getTable(otherTableName) != null, sectionPrefix + "join-field " + fieldName + ", which is referencing an unrecognized table name [" + otherTableName + "]"))
+                  {
+                     List<ExposedJoin> matchedExposedJoins = CollectionUtils.nonNullList(table.getExposedJoins()).stream().filter(ej -> otherTableName.equals(ej.getJoinTable())).toList();
+                     if(assertCondition(CollectionUtils.nullSafeHasContents(matchedExposedJoins), sectionPrefix + "join-field " + fieldName + ", referencing table [" + otherTableName + "] which is not an exposed join on this table."))
+                     {
+                        assertCondition(!matchedExposedJoins.get(0).getIsMany(), sectionPrefix + "join-field " + fieldName + " references an is-many join, which is not supported.");
+                     }
+                     assertCondition(qInstance.getTable(otherTableName).getFields().containsKey(foreignFieldName), sectionPrefix + "join-field " + fieldName + " specifies a fieldName [" + foreignFieldName + "] which does not exist in that table [" + otherTableName + "].");
+                  }
+               }
+               else
+               {
+                  assertCondition(table.getFields().containsKey(fieldName), sectionPrefix + "specifies fieldName " + fieldName + ", which is not a field on this table.");
+               }
+
                assertCondition(!fieldNamesInSections.contains(fieldName), "Table " + table.getName() + " has field " + fieldName + " listed more than once in its field sections.");
 
                fieldNamesInSections.add(fieldName);
@@ -1113,7 +1137,7 @@ public class QInstanceValidator
          }
          else if(hasWidget)
          {
-            assertCondition(qInstance.getWidget(section.getWidgetName()) != null, "Table " + table.getName() + " section " + section.getName() + " specifies widget " + section.getWidgetName() + ", which is not a widget in this instance.");
+            assertCondition(qInstance.getWidget(section.getWidgetName()) != null, sectionPrefix + "specifies widget " + section.getWidgetName() + ", which is not a widget in this instance.");
          }
       }
    }
diff --git a/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidatorTest.java b/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidatorTest.java
index 62d14fbb..84e48161 100644
--- a/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidatorTest.java
+++ b/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/instances/QInstanceValidatorTest.java
@@ -822,6 +822,55 @@ class QInstanceValidatorTest extends BaseTest
 
 
 
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Test
+   void testSectionsWithJoinFields()
+   {
+      Consumer<QTableMetaData> putAllFieldsInASection = table -> table.addSection(new QFieldSection()
+         .withName("section0")
+         .withTier(Tier.T1)
+         .withFieldNames(new ArrayList<>(table.getFields().keySet())));
+
+      assertValidationFailureReasons(qInstance ->
+      {
+         QTableMetaData table = qInstance.getTable(TestUtils.TABLE_NAME_ORDER);
+         putAllFieldsInASection.accept(table);
+         table.getSections().get(0).getFieldNames().add(TestUtils.TABLE_NAME_LINE_ITEM + ".sku");
+      }, "orderLine.sku references an is-many join, which is not supported");
+
+      assertValidationSuccess(qInstance ->
+      {
+         QTableMetaData table = qInstance.getTable(TestUtils.TABLE_NAME_LINE_ITEM);
+         putAllFieldsInASection.accept(table);
+         table.getSections().get(0).getFieldNames().add(TestUtils.TABLE_NAME_ORDER + ".orderNo");
+      });
+
+      assertValidationFailureReasons(qInstance ->
+      {
+         QTableMetaData table = qInstance.getTable(TestUtils.TABLE_NAME_LINE_ITEM);
+         putAllFieldsInASection.accept(table);
+         table.getSections().get(0).getFieldNames().add(TestUtils.TABLE_NAME_ORDER + ".asdf");
+      }, "order.asdf specifies a fieldName [asdf] which does not exist in that table [order].");
+
+      assertValidationFailureReasons(qInstance ->
+      {
+         QTableMetaData table = qInstance.getTable(TestUtils.TABLE_NAME_LINE_ITEM);
+         putAllFieldsInASection.accept(table);
+         table.getSections().get(0).getFieldNames().add("foo.bar");
+      }, "unrecognized table name [foo]");
+
+      assertValidationFailureReasons(qInstance ->
+      {
+         QTableMetaData table = qInstance.getTable(TestUtils.TABLE_NAME_LINE_ITEM);
+         putAllFieldsInASection.accept(table);
+         table.getSections().get(0).getFieldNames().add(TestUtils.TABLE_NAME_SHAPE + ".id");
+      }, "[shape] which is not an exposed join on this table");
+   }
+
+
+
    /*******************************************************************************
     **
     *******************************************************************************/
diff --git a/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/TestUtils.java b/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/TestUtils.java
index a38be542..21942e00 100644
--- a/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/TestUtils.java
+++ b/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/TestUtils.java
@@ -590,6 +590,7 @@ public class TestUtils
             .withFieldName("order.storeId")
             .withJoinNameChain(List.of("orderLineItem")))
          .withAssociation(new Association().withName("extrinsics").withAssociatedTableName(TABLE_NAME_LINE_ITEM_EXTRINSIC).withJoinName("lineItemLineItemExtrinsic"))
+         .withExposedJoin(new ExposedJoin().withJoinTable(TABLE_NAME_ORDER))
          .withField(new QFieldMetaData("id", QFieldType.INTEGER).withIsEditable(false))
          .withField(new QFieldMetaData("createDate", QFieldType.DATE_TIME).withIsEditable(false))
          .withField(new QFieldMetaData("modifyDate", QFieldType.DATE_TIME).withIsEditable(false))