diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index a17f1ac3deb..94261fa2b02 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -141,6 +141,9 @@ Improvements
   classes to use the optimized variants through the MR-JAR mechanism.
   (Uwe Schindler, Robert Muir, Adrien Grand, Mike McCandless)
 
+* LUCENE-8127: Speed up rewriteNoScoring when there are no MUST clauses.
+  (Michael Braun via Adrien Grand)
+
 Bug Fixes
 
 * LUCENE-8077: Fixed bug in how CheckIndex verifies doc-value iterators.
diff --git a/lucene/core/src/java/org/apache/lucene/search/BooleanQuery.java b/lucene/core/src/java/org/apache/lucene/search/BooleanQuery.java
index 8e6df1600cf..f52df9fb9cd 100644
--- a/lucene/core/src/java/org/apache/lucene/search/BooleanQuery.java
+++ b/lucene/core/src/java/org/apache/lucene/search/BooleanQuery.java
@@ -183,6 +183,9 @@ public class BooleanQuery extends Query implements Iterable<BooleanClause> {
   }
 
   private BooleanQuery rewriteNoScoring() {
+    if (clauseSets.get(Occur.MUST).size() == 0) {
+      return this;
+    }
     BooleanQuery.Builder newQuery = new BooleanQuery.Builder();
     newQuery.setMinimumNumberShouldMatch(getMinimumNumberShouldMatch());
     for (BooleanClause clause : clauses) {