diff --git a/docs/changelog/96668.yaml b/docs/changelog/96668.yaml
new file mode 100644
index 0000000000000..483c0f462743f
--- /dev/null
+++ b/docs/changelog/96668.yaml
@@ -0,0 +1,6 @@
+pr: 96668
+summary: Fix iteration of empty percentiles throwing Null Pointer Exception
+area: Aggregations
+type: bug
+issues:
+ - 96626
diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java
index 4abe4200e88bc..a1d6800c66b5c 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java
@@ -21,6 +21,8 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -28,6 +30,7 @@
 
 abstract class AbstractInternalHDRPercentiles extends InternalNumericMetricsAggregation.MultiValue {
 
+    protected static final Iterator<Percentile> EMPTY_ITERATOR = Collections.emptyIterator();
     private static final DoubleHistogram EMPTY_HISTOGRAM_THREE_DIGITS = new DoubleHistogram(3);
     private static final DoubleHistogram EMPTY_HISTOGRAM_ZERO_DIGITS = new EmptyDoubleHdrHistogram();
 
diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java
index ed0ab17ce1004..4fb10c4b170c7 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java
@@ -19,12 +19,16 @@
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
 abstract class AbstractInternalTDigestPercentiles extends InternalNumericMetricsAggregation.MultiValue {
 
+    protected static final Iterator<Percentile> EMPTY_ITERATOR = Collections.emptyIterator();
+
     // NOTE: using compression = 1.0 empty histograms will track just about 5 centroids.
     // This reduces the amount of data to serialize and deserialize.
     private static final TDigestState EMPTY_HISTOGRAM = new EmptyTDigestState();
diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentileRanks.java b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentileRanks.java
index 7a2bf3f5b820d..640e66c6fc96d 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentileRanks.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentileRanks.java
@@ -14,6 +14,7 @@
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Objects;
 
 public class InternalHDRPercentileRanks extends AbstractInternalHDRPercentiles implements PercentileRanks {
     public static final String NAME = "hdr_percentile_ranks";
@@ -43,6 +44,9 @@ public String getWriteableName() {
 
     @Override
     public Iterator<Percentile> iterator() {
+        if (state == null) {
+            return EMPTY_ITERATOR;
+        }
         return new Iter(keys, state);
     }
 
@@ -93,7 +97,7 @@ public static class Iter implements Iterator<Percentile> {
 
         public Iter(double[] values, DoubleHistogram state) {
             this.values = values;
-            this.state = state;
+            this.state = Objects.requireNonNull(state);
             i = 0;
         }
 
diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentiles.java b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentiles.java
index d8a71d19506e3..1ba4656196c77 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentiles.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentiles.java
@@ -14,6 +14,7 @@
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Objects;
 
 public class InternalHDRPercentiles extends AbstractInternalHDRPercentiles implements Percentiles {
     public static final String NAME = "hdr_percentiles";
@@ -43,6 +44,9 @@ public String getWriteableName() {
 
     @Override
     public Iterator<Percentile> iterator() {
+        if (state == null) {
+            return EMPTY_ITERATOR;
+        }
         return new Iter(keys, state);
     }
 
@@ -83,7 +87,7 @@ public static class Iter implements Iterator<Percentile> {
 
         public Iter(double[] percents, DoubleHistogram state) {
             this.percents = percents;
-            this.state = state;
+            this.state = Objects.requireNonNull(state);
             i = 0;
         }
 
diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java
index c0c79afc494cf..9fc1c5980faf9 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java
@@ -13,6 +13,7 @@
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Objects;
 
 public class InternalTDigestPercentileRanks extends AbstractInternalTDigestPercentiles implements PercentileRanks {
     public static final String NAME = "tdigest_percentile_ranks";
@@ -42,6 +43,9 @@ public String getWriteableName() {
 
     @Override
     public Iterator<Percentile> iterator() {
+        if (state == null) {
+            return EMPTY_ITERATOR;
+        }
         return new Iter(keys, state);
     }
 
@@ -89,7 +93,7 @@ public static class Iter implements Iterator<Percentile> {
 
         public Iter(double[] values, TDigestState state) {
             this.values = values;
-            this.state = state;
+            this.state = Objects.requireNonNull(state);
             i = 0;
         }
 
diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentiles.java b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentiles.java
index bf4f08f126797..f3aea151b1112 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentiles.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentiles.java
@@ -13,6 +13,7 @@
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Objects;
 
 public class InternalTDigestPercentiles extends AbstractInternalTDigestPercentiles implements Percentiles {
     public static final String NAME = "tdigest_percentiles";
@@ -42,6 +43,9 @@ public String getWriteableName() {
 
     @Override
     public Iterator<Percentile> iterator() {
+        if (state == null) {
+            return EMPTY_ITERATOR;
+        }
         return new Iter(keys, state);
     }
 
@@ -79,7 +83,7 @@ public static class Iter implements Iterator<Percentile> {
 
         public Iter(double[] percents, TDigestState state) {
             this.percents = percents;
-            this.state = state;
+            this.state = Objects.requireNonNull(state);
             i = 0;
         }
 
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/AbstractPercentilesTestCase.java b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/AbstractPercentilesTestCase.java
index 6f8b554500433..d5867c8ebefcd 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/AbstractPercentilesTestCase.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/AbstractPercentilesTestCase.java
@@ -24,9 +24,11 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.function.Predicate;
 import java.util.stream.Stream;
 
+import static java.util.Collections.emptyMap;
 import static java.util.stream.Collectors.toList;
 import static org.hamcrest.Matchers.equalTo;
 import static org.mockito.Mockito.mock;
@@ -55,7 +57,7 @@ private T createTestInstance(String name, Map<String, Object> metadata, boolean
         for (int i = 0; i < numValues; ++i) {
             values[i] = randomDouble();
         }
-        return createTestInstance(name, metadata, keyed, format, percents, values);
+        return createTestInstance(name, metadata, keyed, format, percents, values, false);
     }
 
     protected abstract T createTestInstance(
@@ -64,7 +66,8 @@ protected abstract T createTestInstance(
         boolean keyed,
         DocValueFormat format,
         double[] percents,
-        double[] values
+        double[] values,
+        boolean empty
     );
 
     protected abstract Class<? extends ParsedPercentiles> implementationClass();
@@ -104,7 +107,7 @@ public void testEmptyRanksXContent() throws IOException {
         boolean keyed = randomBoolean();
         DocValueFormat docValueFormat = randomNumericDocValueFormat();
 
-        T agg = createTestInstance("test", Collections.emptyMap(), keyed, docValueFormat, percents, new double[0]);
+        T agg = createTestInstance("test", Collections.emptyMap(), keyed, docValueFormat, percents, new double[0], false);
 
         for (Percentile percentile : agg) {
             Double value = percentile.getValue();
@@ -147,4 +150,26 @@ public void testEmptyRanksXContent() throws IOException {
 
         assertThat(Strings.toString(builder), equalTo(expected));
     }
+
+    public void testEmptyIterator() {
+        final double[] percents = randomPercents(false);
+
+        final Iterable<?> aggregation = createTestInstance(
+            "test",
+            emptyMap(),
+            false,
+            randomNumericDocValueFormat(),
+            percents,
+            new double[] {},
+            true
+        );
+
+        for (var ignored : aggregation) {
+            fail("empty expected");
+        }
+
+        final Iterator<?> it = aggregation.iterator();
+        assertFalse(it.hasNext());
+        expectThrows(NoSuchElementException.class, it::next);
+    }
 }
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java
index 47015201f58f5..ac43929878f47 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java
@@ -30,9 +30,13 @@ protected InternalHDRPercentileRanks createTestInstance(
         boolean keyed,
         DocValueFormat format,
         double[] percents,
-        double[] values
+        double[] values,
+        boolean empty
     ) {
 
+        if (empty) {
+            return new InternalHDRPercentileRanks(name, percents, null, keyed, format, metadata);
+        }
         final DoubleHistogram state = new DoubleHistogram(3);
         Arrays.stream(values).forEach(state::recordValue);
 
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesTests.java
index 6e986f69c1c50..1c9cb88ee3e2b 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalHDRPercentilesTests.java
@@ -31,9 +31,14 @@ protected InternalHDRPercentiles createTestInstance(
         boolean keyed,
         DocValueFormat format,
         double[] percents,
-        double[] values
+        double[] values,
+        boolean empty
     ) {
 
+        if (empty) {
+            return new InternalHDRPercentiles(name, percents, null, keyed, format, metadata);
+        }
+
         final DoubleHistogram state = new DoubleHistogram(3);
         Arrays.stream(values).forEach(state::recordValue);
 
@@ -76,7 +81,15 @@ public void testIterator() {
             values[i] = randomDouble();
         }
 
-        InternalHDRPercentiles aggregation = createTestInstance("test", emptyMap(), false, randomNumericDocValueFormat(), percents, values);
+        InternalHDRPercentiles aggregation = createTestInstance(
+            "test",
+            emptyMap(),
+            false,
+            randomNumericDocValueFormat(),
+            percents,
+            values,
+            false
+        );
 
         Iterator<Percentile> iterator = aggregation.iterator();
         Iterator<String> nameIterator = aggregation.valueNames().iterator();
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesRanksTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesRanksTests.java
index 27d3fafee1319..cdefca8f72eaf 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesRanksTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesRanksTests.java
@@ -29,8 +29,12 @@ protected InternalTDigestPercentileRanks createTestInstance(
         boolean keyed,
         DocValueFormat format,
         double[] percents,
-        double[] values
+        double[] values,
+        boolean empty
     ) {
+        if (empty) {
+            return new InternalTDigestPercentileRanks(name, percents, null, keyed, format, metadata);
+        }
         final TDigestState state = new TDigestState(100);
         Arrays.stream(values).forEach(state::add);
 
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesTests.java
index 5c8e6aa2700c9..1df9e8152101f 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTDigestPercentilesTests.java
@@ -30,8 +30,12 @@ protected InternalTDigestPercentiles createTestInstance(
         boolean keyed,
         DocValueFormat format,
         double[] percents,
-        double[] values
+        double[] values,
+        boolean empty
     ) {
+        if (empty) {
+            return new InternalTDigestPercentiles(name, percents, null, keyed, format, metadata);
+        }
         final TDigestState state = new TDigestState(100);
         Arrays.stream(values).forEach(state::add);
 
@@ -126,7 +130,8 @@ public void testIterator() {
             false,
             randomNumericDocValueFormat(),
             percents,
-            values
+            values,
+            false
         );
 
         Iterator<Percentile> iterator = aggregation.iterator();