diff --git a/lcviz/conftest.py b/lcviz/conftest.py
index 6d61690..767828c 100644
--- a/lcviz/conftest.py
+++ b/lcviz/conftest.py
@@ -37,6 +37,9 @@ def light_curve_like_kepler_quarter(seed=42):
     )
     lc['flux_alt'] = flux + 1
     lc['flux_alt_err'] = flux_err
+    lc.meta['MISSION'] = 'KEPLER'
+    lc.meta['QUARTER'] = 10
+
     return lc
 
 
diff --git a/lcviz/parsers.py b/lcviz/parsers.py
index 4c32b87..4f6f779 100644
--- a/lcviz/parsers.py
+++ b/lcviz/parsers.py
@@ -8,6 +8,12 @@
 
 __all__ = ["light_curve_parser"]
 
+mission_sub_intervals = {
+    'kepler': {'prefix': 'Q', 'card': 'QUARTER'},
+    'k2': {'prefix': 'C', 'card': 'CAMPAIGN'},
+    'tess': {'prefix': 'S', 'card': 'SECTOR'},
+}
+
 
 @data_parser_registry("light_curve_parser")
 def light_curve_parser(app, file_obj, data_label=None, show_in_viewer=True, **kwargs):
@@ -40,14 +46,19 @@ def light_curve_parser(app, file_obj, data_label=None, show_in_viewer=True, **kw
     # handle flux_origin default
     mission = light_curve.meta.get('MISSION', '').lower()
     flux_origin = light_curve.meta.get('FLUX_ORIGIN', None)  # i.e. PDCSAP or SAP
+
     if isinstance(light_curve, lightkurve.targetpixelfile.TargetPixelFile):
         new_data_label += '[TPF]'
-    elif mission == 'kepler':
-        new_data_label += f' Q{light_curve.meta.get("QUARTER")}'
-    elif mission == 'k2':
-        new_data_label += f' C{light_curve.meta.get("CAMPAIGN")}'
-    elif mission == 'tess':
-        new_data_label += f' S{light_curve.meta.get("SECTOR")}'
+    elif mission in mission_sub_intervals:
+        # the sub-interval label is something like "Q9" for Kepler or
+        # "S9" for TESS. If it's already in the proposed data label, skip;
+        # otherwise, append it.
+        sub_interval_label = (
+            f'{mission_sub_intervals[mission]["prefix"]}'
+            f'{light_curve.meta.get(mission_sub_intervals[mission]["card"])}'
+        )
+        if sub_interval_label not in new_data_label:
+            new_data_label += f' [{sub_interval_label}]'
 
     if flux_origin == 'flux' or (flux_origin is None and 'flux' in getattr(light_curve, 'columns', [])):  # noqa
         # then make a copy of this column so it won't be lost when changing with the flux_column
diff --git a/lcviz/tests/test_parser.py b/lcviz/tests/test_parser.py
index a37b343..dd9e9cc 100644
--- a/lcviz/tests/test_parser.py
+++ b/lcviz/tests/test_parser.py
@@ -119,3 +119,14 @@ def test_apply_yrangerois(helper, light_curve_like_kepler_quarter):
     subset_state = subsets['Subset 1'][0]['subset_state']
 
     np.testing.assert_allclose([subset_state.lo, subset_state.hi], [1, 1.05])
+
+
+def test_data_label(helper, light_curve_like_kepler_quarter):
+    # add data without specifying data label:
+    helper.load_data(light_curve_like_kepler_quarter)
+    assert helper.app.data_collection[-1].label == 'Light curve [Q10]'
+
+    # specify label with a quarter, check that quarter isn't appended:
+    data_label = 'Cool target in Q10'
+    helper.load_data(light_curve_like_kepler_quarter, data_label=data_label)
+    assert helper.app.data_collection[-1].label == data_label