diff --git a/src/main/java/com/saucelabs/saucerest/model/insights/AnalyticsTrendsParameter.java b/src/main/java/com/saucelabs/saucerest/model/insights/AnalyticsTrendsParameter.java
index 2d85bc08..fcfc551a 100644
--- a/src/main/java/com/saucelabs/saucerest/model/insights/AnalyticsTrendsParameter.java
+++ b/src/main/java/com/saucelabs/saucerest/model/insights/AnalyticsTrendsParameter.java
@@ -143,6 +143,9 @@ public AnalyticsTrendsParameter build() {
             if (isTimeRangeUsed && isStartEndUsed) {
                 throw new IllegalStateException("Only one of 'time_range' or 'start' and 'end' can be set, not both.");
             }
+            if (interval == null) {
+                interval = Interval.ONE_DAY;
+            }
 
             return new AnalyticsTrendsParameter(this);
         }
diff --git a/src/test/java/com/saucelabs/saucerest/unit/AnalyticsTrendsParameterTest.java b/src/test/java/com/saucelabs/saucerest/unit/AnalyticsTrendsParameterTest.java
index dee4b014..28ab35bd 100644
--- a/src/test/java/com/saucelabs/saucerest/unit/AnalyticsTrendsParameterTest.java
+++ b/src/test/java/com/saucelabs/saucerest/unit/AnalyticsTrendsParameterTest.java
@@ -28,4 +28,14 @@ public void testToMapWithTimeRange() {
     public void testBuildThrowsWhenNeitherTimeRangeNorStartEndSet() {
         assertThrows(IllegalStateException.class, () -> new AnalyticsTrendsParameter.Builder().build());
     }
+
+    @Test
+    public void testToMapDefaultsIntervalWhenNotSet() {
+        AnalyticsTrendsParameter params = new AnalyticsTrendsParameter.Builder()
+                .setTimeRange(new TimeRange(1, Unit.H))
+                .build();
+
+        Map<String, Object> map = params.toMap();
+        assertEquals("1d", map.get("interval"));
+    }
 }