diff --git a/ethereum/statetransition/src/main/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidator.java b/ethereum/statetransition/src/main/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidator.java
index 0e5968a89c4..7812077bd95 100644
--- a/ethereum/statetransition/src/main/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidator.java
+++ b/ethereum/statetransition/src/main/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidator.java
@@ -89,6 +89,18 @@ public SafeFuture<InternalValidationResult> validate(final SignedBlobSidecar sig
     tech.pegasys.teku.networking.eth2.gossip.BlobSidecarGossipManager.TopicSubnetIdAwareOperationProcessor
      */
 
+    /*
+    [REJECT] The sidecar's index is consistent with `MAX_BLOBS_PER_BLOCK` -- i.e. `sidecar.index < MAX_BLOBS_PER_BLOCK`
+     */
+    final Optional<Integer> maxBlobsPerBlockAtSlot =
+        spec.getMaxBlobsPerBlock(blobSidecar.getSlot());
+    if (maxBlobsPerBlockAtSlot.isEmpty()) {
+      return completedFuture(reject("BlobSidecar's slot is pre deneb"));
+    }
+    if (blobSidecar.getIndex().isGreaterThanOrEqualTo(maxBlobsPerBlockAtSlot.get())) {
+      return completedFuture(reject("BlobSidecar index is greater than MAX_BLOBS_PER_BLOCK"));
+    }
+
     /*
     [REJECT] The sidecar's block's parent (defined by sidecar.block_parent_root) passes validation.
      */
diff --git a/ethereum/statetransition/src/test/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidatorTest.java b/ethereum/statetransition/src/test/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidatorTest.java
index ee8b6065077..f57069c4b34 100644
--- a/ethereum/statetransition/src/test/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidatorTest.java
+++ b/ethereum/statetransition/src/test/java/tech/pegasys/teku/statetransition/validation/BlobSidecarValidatorTest.java
@@ -27,6 +27,7 @@
 import tech.pegasys.teku.infrastructure.async.SafeFuture;
 import tech.pegasys.teku.infrastructure.async.SafeFutureAssert;
 import tech.pegasys.teku.infrastructure.unsigned.UInt64;
+import tech.pegasys.teku.spec.Spec;
 import tech.pegasys.teku.spec.SpecMilestone;
 import tech.pegasys.teku.spec.TestSpecContext;
 import tech.pegasys.teku.spec.TestSpecInvocationContextProvider.SpecContext;
@@ -101,6 +102,36 @@ void shouldAccept() {
         .isCompletedWithValueMatching(InternalValidationResult::isAccept);
   }
 
+  @TestTemplate
+  void shouldRejectWhenIndexIsTooBig(final SpecContext specContext) {
+
+    signedBlobSidecar =
+        specContext
+            .getDataStructureUtil()
+            .createRandomBlobSidecarBuilder()
+            .slot(slot)
+            .index(UInt64.valueOf(specContext.getSpec().getMaxBlobsPerBlock().orElseThrow()))
+            .proposerIndex(proposerIndex)
+            .blockRoot(blockRoot)
+            .blockParentRoot(blockParentRoot)
+            .buildSigned();
+
+    SafeFutureAssert.assertThatSafeFuture(blobSidecarValidator.validate(signedBlobSidecar))
+        .isCompletedWithValueMatching(InternalValidationResult::isReject);
+  }
+
+  @TestTemplate
+  void shouldRejectWhenSlotIsNotDeneb() {
+    final Spec mockedSpec = mock(Spec.class);
+    when(mockedSpec.getMaxBlobsPerBlock(slot)).thenReturn(Optional.empty());
+
+    blobSidecarValidator =
+        BlobSidecarValidator.create(mockedSpec, invalidBlocks, gossipValidationHelper);
+
+    SafeFutureAssert.assertThatSafeFuture(blobSidecarValidator.validate(signedBlobSidecar))
+        .isCompletedWithValueMatching(InternalValidationResult::isReject);
+  }
+
   @TestTemplate
   void shouldRejectWhenParentBlockInvalid() {
     invalidBlocks.put(blockParentRoot, BlockImportResult.FAILED_INVALID_ANCESTRY);