diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 7391f268757..0a0a265c8b0 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -162,6 +162,8 @@ Bug Fixes
 
 * GITHUB#12158: KeywordField#newSetQuery should clone input BytesRef[] to avoid modifying provided array. (Greg Miller)
 
+* GITHUB#12196: Fix MultiFieldQueryParser to handle both query boost and phrase slop at the same time.  (Jasir KT)
+
 Build
 ---------------------
 
diff --git a/lucene/queryparser/src/java/org/apache/lucene/queryparser/classic/MultiFieldQueryParser.java b/lucene/queryparser/src/java/org/apache/lucene/queryparser/classic/MultiFieldQueryParser.java
index a269901bb42..eb9abad7813 100644
--- a/lucene/queryparser/src/java/org/apache/lucene/queryparser/classic/MultiFieldQueryParser.java
+++ b/lucene/queryparser/src/java/org/apache/lucene/queryparser/classic/MultiFieldQueryParser.java
@@ -124,6 +124,10 @@ public class MultiFieldQueryParser extends QueryParser {
       if (slop != mpq.getSlop()) {
         q = new MultiPhraseQuery.Builder(mpq).setSlop(slop).build();
       }
+    } else if (q instanceof BoostQuery boostQuery) {
+      Query subQuery = boostQuery.getQuery();
+      subQuery = applySlop(subQuery, slop);
+      q = new BoostQuery(subQuery, boostQuery.getBoost());
     }
     return q;
   }
diff --git a/lucene/queryparser/src/test/org/apache/lucene/queryparser/classic/TestMultiFieldQueryParser.java b/lucene/queryparser/src/test/org/apache/lucene/queryparser/classic/TestMultiFieldQueryParser.java
index 57ed0e70972..ee684c30f85 100644
--- a/lucene/queryparser/src/test/org/apache/lucene/queryparser/classic/TestMultiFieldQueryParser.java
+++ b/lucene/queryparser/src/test/org/apache/lucene/queryparser/classic/TestMultiFieldQueryParser.java
@@ -156,6 +156,11 @@ public class TestMultiFieldQueryParser extends LuceneTestCase {
     q = mfqp.parse("one AND two AND foo:test");
     assertEquals("+((b:one)^5.0 (t:one)^10.0) +((b:two)^5.0 (t:two)^10.0) +foo:test", q.toString());
 
+    // Check boost with slop
+    // See https://github.com/apache/lucene/issues/12195
+    q = mfqp.parse("\"one two\"~2");
+    assertEquals("(b:\"one two\"~2)^5.0 (t:\"one two\"~2)^10.0", q.toString());
+
     q = mfqp.parse("one^3 AND two^4");
     assertEquals("+((b:one)^5.0 (t:one)^10.0)^3.0 +((b:two)^5.0 (t:two)^10.0)^4.0", q.toString());
   }