rishi02102017 · Nov 14, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -26,6 +26,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Fix `mpl_to_plotly` conversion of matplotlib contour lines and line collections: close contour rings ending with `Z` codes, support dash styles, convert date x-axes, separate disjoint subpaths with `None` separators, hide line collection traces from the legend by default, and group consecutive same-style lines into single traces [[#5770](https://github.com/plotly/plotly.py/pull/5770)], with thanks to @robertoffmoura for the contribution!
 - Fix `plotly.io.write_images` ignoring `layout.width`/`layout.height` (and the template's) and exporting every figure at the default 700x500 size; it now uses the same width/height priority as `write_image` and `to_image` [[#5784](https://github.com/plotly/plotly.py/pull/5784)], with thanks to @breken-ai for the contribution!
 - Fix color utilities mutating the list of colors passed to them [[#5836](https://github.com/plotly/plotly.py/pull/5836)], with thanks to @Enesuygurs for the contribution!
+- Fix Plotly Express (including `px.imshow`) ignoring `facet_row_spacing=0` and `facet_col_spacing=0` and using the default spacing between facets instead [[#5881](https://github.com/plotly/plotly.py/pull/5881)], with thanks to @rishi02102017 for the contribution!
 
 
 ## [7.1.0] - 2026-09-15

diff --git a/plotly/express/_core.py b/plotly/express/_core.py
@@ -2869,6 +2869,8 @@ def init_figure(args, subplot_type, frame_list, nrows, ncols, col_labels, row_la
     column_widths = [1.0] * ncols
     row_heights = [1.0] * nrows
     facet_col_wrap = args.get("facet_col_wrap", 0)
+    facet_row_spacing = args.get("facet_row_spacing")
+    facet_col_spacing = args.get("facet_col_spacing")
 
     # Build column_widths/row_heights
     if subplot_type == "xy":
@@ -2881,9 +2883,9 @@ def init_figure(args, subplot_type, frame_list, nrows, ncols, col_labels, row_la
             row_heights = [main_size] * (nrows - 1) + [1 - main_size]
             vertical_spacing = 0.01
         elif facet_col_wrap:
-            vertical_spacing = args.get("facet_row_spacing") or 0.07
+            vertical_spacing = 0.07 if facet_row_spacing is None else facet_row_spacing
         else:
-            vertical_spacing = args.get("facet_row_spacing") or 0.03
+            vertical_spacing = 0.03 if facet_row_spacing is None else facet_row_spacing
 
         if args.get("marginal_y") is not None:
             if args["marginal_y"] == "histogram" or ("color" in args and args["color"]):
@@ -2894,18 +2896,20 @@ def init_figure(args, subplot_type, frame_list, nrows, ncols, col_labels, row_la
             column_widths = [main_size] * (ncols - 1) + [1 - main_size]
             horizontal_spacing = 0.005
         else:
-            horizontal_spacing = args.get("facet_col_spacing") or 0.02
+            horizontal_spacing = (
+                0.02 if facet_col_spacing is None else facet_col_spacing
+            )
     else:
         # Other subplot types:
         #   'scene', 'geo', 'polar', 'ternary', 'map', 'domain', None
         #
         # We can customize subplot spacing per type once we enable faceting
         # for all plot types
         if facet_col_wrap:
-            vertical_spacing = args.get("facet_row_spacing") or 0.07
+            vertical_spacing = 0.07 if facet_row_spacing is None else facet_row_spacing
         else:
-            vertical_spacing = args.get("facet_row_spacing") or 0.03
-        horizontal_spacing = args.get("facet_col_spacing") or 0.02
+            vertical_spacing = 0.03 if facet_row_spacing is None else facet_row_spacing
+        horizontal_spacing = 0.02 if facet_col_spacing is None else facet_col_spacing
 
     if facet_col_wrap:
         subplot_labels = [None] * nrows * ncols

diff --git a/tests/test_optional/test_px/test_facets.py b/tests/test_optional/test_px/test_facets.py
@@ -46,6 +46,37 @@ def test_facets(backend):
     assert fig.layout.yaxis4.domain[0] - fig.layout.yaxis.domain[1] == approx(0.08)
 
 
+def test_facets_zero_spacing(backend):
+    df = px.data.tips(return_type=backend)
+
+    fig = px.scatter(
+        df,
+        x="total_bill",
+        y="tip",
+        facet_row="sex",
+        facet_col="smoker",
+        facet_col_spacing=0,
+        facet_row_spacing=0,
+    )
+    assert fig.layout.xaxis4.domain[0] - fig.layout.xaxis.domain[1] == approx(0)
+    assert fig.layout.yaxis4.domain[0] - fig.layout.yaxis.domain[1] == approx(0)
+
+    fig = px.scatter(
+        df,
+        x="total_bill",
+        y="tip",
+        facet_col="day",
+        facet_col_wrap=2,
+        facet_col_spacing=0,
+        facet_row_spacing=0,
+    )
+    assert fig.layout.xaxis4.domain[0] - fig.layout.xaxis.domain[1] == approx(0)
+    assert fig.layout.yaxis4.domain[0] - fig.layout.yaxis.domain[1] == approx(0)
+
+    fig = px.pie(df, values="tip", names="day", facet_col="smoker", facet_col_spacing=0)
+    assert fig.data[1].domain.x[0] - fig.data[0].domain.x[1] == approx(0)
+
+
 def test_facets_with_marginals(backend):
     df = px.data.tips(return_type=backend)
 

diff --git a/tests/test_optional/test_px/test_imshow.py b/tests/test_optional/test_px/test_imshow.py
@@ -553,3 +553,12 @@ def test_imshow_xarray_facet_row_and_col():
     annotations = [a.text for a in fig.layout.annotations]
     assert any("row_dim=R1" in a for a in annotations)
     assert any("col_dim=C1" in a for a in annotations)
+
+
+def test_imshow_facet_spacing_zero():
+    img = np.random.random((2, 3, 5, 6))
+    fig = px.imshow(
+        img, facet_row=0, facet_col=1, facet_row_spacing=0, facet_col_spacing=0
+    )
+    assert fig.layout.xaxis2.domain[0] - fig.layout.xaxis.domain[1] == pytest.approx(0)
+    assert fig.layout.yaxis4.domain[0] - fig.layout.yaxis.domain[1] == pytest.approx(0)