diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index f876ca4e6..25d0ee02b 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -51,6 +51,7 @@ The <action> type attribute can be add,update,fix,remove.
     <action issue="LANG-1600" type="fix" dev="ggregory" due-to="Michael F">Restore handling of collections for non-JSON ToStringStyle #610.</action>
     <action                   type="fix" dev="ggregory" due-to="iamchao1129">ContextedException Javadoc add missing semicolon #581.</action>
     <!--  UPDATES -->
+    <action issue="LANG-1606" type="update" dev="sebb" due-to="Rustem Galiev">StringUtils.countMatches - clarify Javadoc.</action>
     <action issue="LANG-1591" type="update" dev="kinow" due-to="bhawna94">Remove redundant argument from substring call.</action>
     <action issue="LANG-1579" type="update" dev="aherbert" due-to="XenoAmess">Improve StringUtils.stripAccents conversion of remaining accents.</action>
     <action issue="LANG-1596" type="update" dev="aherbert" due-to="Richard Eckart de Castilho">ArrayUtils.toPrimitive(Object) does not support boolean and other types #607.</action>
diff --git a/src/main/java/org/apache/commons/lang3/StringUtils.java b/src/main/java/org/apache/commons/lang3/StringUtils.java
index a93d34a7f..0949398ad 100644
--- a/src/main/java/org/apache/commons/lang3/StringUtils.java
+++ b/src/main/java/org/apache/commons/lang3/StringUtils.java
@@ -1425,7 +1425,8 @@ public class StringUtils {
     // Count matches
     //-----------------------------------------------------------------------
     /**
-     * <p>Counts how many times the substring appears in the larger string.</p>
+     * <p>Counts how many times the substring appears in the larger string.
+     * Note that the code only counts non-overlapping matches.</p>
      *
      * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
      *
@@ -1437,6 +1438,7 @@ public class StringUtils {
      * StringUtils.countMatches("abba", "a")   = 2
      * StringUtils.countMatches("abba", "ab")  = 1
      * StringUtils.countMatches("abba", "xxx") = 0
+     * StringUtils.countMatches("ababa", "aba") = 1
      * </pre>
      *
      * @param str  the CharSequence to check, may be null
diff --git a/src/test/java/org/apache/commons/lang3/StringUtilsSubstringTest.java b/src/test/java/org/apache/commons/lang3/StringUtilsSubstringTest.java
index 9a1c014fe..d876d7c94 100644
--- a/src/test/java/org/apache/commons/lang3/StringUtilsSubstringTest.java
+++ b/src/test/java/org/apache/commons/lang3/StringUtilsSubstringTest.java
@@ -349,6 +349,14 @@ public class StringUtilsSubstringTest  {
              StringUtils.countMatches("one long someone sentence of one", "two"));
         assertEquals(4,
              StringUtils.countMatches("oooooooooooo", "ooo"));
+        assertEquals(0, StringUtils.countMatches(null, "?"));
+        assertEquals(0, StringUtils.countMatches("", "?"));
+        assertEquals(0, StringUtils.countMatches("abba", null));
+        assertEquals(0, StringUtils.countMatches("abba", ""));
+        assertEquals(2, StringUtils.countMatches("abba", "a"));
+        assertEquals(1, StringUtils.countMatches("abba", "ab"));
+        assertEquals(0, StringUtils.countMatches("abba", "xxx"));
+        assertEquals(1, StringUtils.countMatches("ababa", "aba"));
     }
 
     @Test