diff --git a/xrspatial/geotiff/__init__.py b/xrspatial/geotiff/__init__.py
index dd82d693..1adedd8b 100644
--- a/xrspatial/geotiff/__init__.py
+++ b/xrspatial/geotiff/__init__.py
@@ -2282,6 +2282,14 @@ def read_geotiff_dask(source: str, *,
         coords = _geo_to_coords(geo_info, full_h, full_w)
 
     if band is not None:
+        # Reject ``bool`` and ``np.bool_`` up front; ``isinstance(True, int)``
+        # is True in Python so ``True < n_bands`` evaluates without raising
+        # and silently reads band 1. ``np.bool_`` is not a subclass of
+        # ``bool`` so it needs its own check to match the VRT path's
+        # rejection. See #1786.
+        if isinstance(band, (bool, np.bool_)):
+            raise ValueError(
+                f"band must be a non-negative int, got {band!r}")
         if n_bands == 0:
             if band != 0:
                 raise IndexError(
@@ -2967,6 +2975,15 @@ def read_geotiff_gpu(source: str, *,
         # behaviour mirrors ``read_geotiff_dask``.
         ifd_samples = ifd.samples_per_pixel
         if band is not None:
+            # Reject ``bool`` and ``np.bool_`` up front;
+            # ``isinstance(True, int)`` is True in Python so
+            # ``True < ifd_samples`` evaluates without raising and silently
+            # reads band 1. ``np.bool_`` is not a subclass of ``bool`` so it
+            # needs its own check to match the VRT path's rejection.
+            # See #1786.
+            if isinstance(band, (bool, np.bool_)):
+                raise ValueError(
+                    f"band must be a non-negative int, got {band!r}")
             if ifd_samples <= 1:
                 if band != 0:
                     raise IndexError(
diff --git a/xrspatial/geotiff/_reader.py b/xrspatial/geotiff/_reader.py
index beb151b4..d5790c64 100644
--- a/xrspatial/geotiff/_reader.py
+++ b/xrspatial/geotiff/_reader.py
@@ -1898,6 +1898,15 @@ def _read_cog_http(url: str, overview_level: int | None = None,
     # urllib3 ``PoolManager`` is shared module-level, not per-source)
     # but a future resource-holding source will need it. See issue #1695.
     if band is not None:
+        # Reject ``bool`` (and ``np.bool_``) up front; ``isinstance(True, int)``
+        # is True in Python so ``True < samples_per_pixel`` evaluates without
+        # raising and silently reads band 1. ``np.bool_`` is not a subclass of
+        # ``bool`` so it needs its own check to match the VRT path's
+        # rejection. See #1786.
+        if isinstance(band, (bool, np.bool_)):
+            source.close()
+            raise ValueError(
+                f"band must be a non-negative int, got {band!r}")
         if ifd.samples_per_pixel <= 1:
             if band != 0:
                 source.close()
@@ -2383,6 +2392,16 @@ def read_to_array(source, *, window=None, overview_level: int | None = None,
         # index only. See issue #1673.
         ifd_samples = ifd.samples_per_pixel
         if band is not None:
+            # Reject ``bool`` and ``np.bool_`` before the range check.
+            # ``isinstance(True, int)`` is True in Python and
+            # ``True < ifd_samples`` evaluates as ``1``, so without this
+            # guard ``band=True`` silently reads band 1 and ``band=False``
+            # reads band 0. ``np.bool_`` is not a subclass of ``bool`` so it
+            # needs its own check to match the VRT path's existing
+            # rejection. See #1786.
+            if isinstance(band, (bool, np.bool_)):
+                raise ValueError(
+                    f"band must be a non-negative int, got {band!r}")
             if ifd_samples <= 1:
                 if band != 0:
                     raise IndexError(
diff --git a/xrspatial/geotiff/tests/test_geotiff_band_bool_rejection_1786.py b/xrspatial/geotiff/tests/test_geotiff_band_bool_rejection_1786.py
new file mode 100644
index 00000000..dc2391fe
--- /dev/null
+++ b/xrspatial/geotiff/tests/test_geotiff_band_bool_rejection_1786.py
@@ -0,0 +1,290 @@
+"""Regression tests for issue #1786.
+
+Every non-VRT read path range-checks ``band`` but does not reject
+``bool``. Because ``isinstance(True, int)`` is True in Python and
+``True < N`` evaluates as ``1 < N``, ``band=True`` silently reads
+band 1 and ``band=False`` reads band 0. The VRT path
+(``_vrt.read_vrt``) already rejects bools up front (#1673 follow-up)
+so the API contract is inconsistent across read paths.
+
+These tests pin every read entry point -- ``read_to_array`` (local
+and HTTP), ``open_geotiff``, ``read_geotiff_dask``,
+``read_geotiff_gpu`` (when cupy is available), and ``read_vrt`` --
+to the same rejection so all four backends agree: ``band`` must be
+a non-negative int, never a bool.
+"""
+from __future__ import annotations
+
+import importlib.util
+import uuid
+
+import numpy as np
+import pytest
+import xarray as xr
+
+
+def _gpu_available() -> bool:
+    if importlib.util.find_spec("cupy") is None:
+        return False
+    try:
+        import cupy
+        return bool(cupy.cuda.is_available())
+    except Exception:
+        return False
+
+
+_HAS_GPU = _gpu_available()
+_gpu_only = pytest.mark.skipif(not _HAS_GPU, reason="cupy + CUDA required")
+
+
+@pytest.fixture
+def multiband_tiff_path(tmp_path):
+    """4x6 three-band tiled tiff for the bool-rejection tests."""
+    from xrspatial.geotiff import to_geotiff
+
+    arr = np.arange(72, dtype=np.float32).reshape(4, 6, 3)
+    da = xr.DataArray(
+        arr,
+        dims=['y', 'x', 'band'],
+        coords={
+            'y': np.array([0.5, 1.5, 2.5, 3.5]),
+            'x': np.array([0.5, 1.5, 2.5, 3.5, 4.5, 5.5]),
+            'band': [0, 1, 2],
+        },
+        attrs={'crs': 4326},
+    )
+    p = tmp_path / 'mb_1786.tif'
+    to_geotiff(da, str(p), tile_size=16)
+    return str(p), arr
+
+
+def _write_vrt_xml(vrt_path: str, source_filename: str, size_h: int,
+                   size_w: int, n_bands: int) -> None:
+    bands_xml = ""
+    for b in range(1, n_bands + 1):
+        bands_xml += (
+            f'  <VRTRasterBand dataType="Float32" band="{b}">\n'
+            '    <SimpleSource>\n'
+            f'      <SourceFilename relativeToVRT="1">{source_filename}'
+            '</SourceFilename>\n'
+            f'      <SourceBand>{b}</SourceBand>\n'
+            f'      <SrcRect xOff="0" yOff="0" xSize="{size_w}" '
+            f'ySize="{size_h}"/>\n'
+            f'      <DstRect xOff="0" yOff="0" xSize="{size_w}" '
+            f'ySize="{size_h}"/>\n'
+            '    </SimpleSource>\n'
+            '  </VRTRasterBand>\n'
+        )
+    xml = (
+        f'<VRTDataset rasterXSize="{size_w}" rasterYSize="{size_h}">\n'
+        '  <GeoTransform>0, 1, 0, 0, 0, -1</GeoTransform>\n'
+        f'{bands_xml}'
+        '</VRTDataset>\n'
+    )
+    with open(vrt_path, 'w') as f:
+        f.write(xml)
+
+
+@pytest.fixture
+def multiband_vrt_path(tmp_path, multiband_tiff_path):
+    """A 3-band VRT wrapping the same multi-band TIFF used above."""
+    src_tif, _ = multiband_tiff_path
+    d = tmp_path / f'vrt_1786_{uuid.uuid4().hex[:8]}'
+    d.mkdir()
+    # The VRT needs the source TIFF inside (or under an allowed root)
+    # for path-containment (#1671). Copy bytes rather than symlink so
+    # the test does not depend on the platform's symlink behaviour.
+    import shutil
+    local_tif = d / 'data.tif'
+    shutil.copy(src_tif, local_tif)
+    vrt_path = d / 'mosaic.vrt'
+    _write_vrt_xml(str(vrt_path), 'data.tif', size_h=4, size_w=6,
+                   n_bands=3)
+    return str(vrt_path)
+
+
+# ---------------------------------------------------------------------------
+# read_to_array (local eager path)
+# ---------------------------------------------------------------------------
+
+
+def test_read_to_array_band_true_rejected(multiband_tiff_path):
+    """``band=True`` no longer silently reads band 1."""
+    from xrspatial.geotiff._reader import read_to_array
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_to_array(path, band=True)
+
+
+def test_read_to_array_band_false_rejected(multiband_tiff_path):
+    """``band=False`` no longer silently reads band 0."""
+    from xrspatial.geotiff._reader import read_to_array
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_to_array(path, band=False)
+
+
+def test_read_to_array_band_zero_still_works(multiband_tiff_path):
+    """``band=0`` is a plain int and still selects band 0."""
+    from xrspatial.geotiff._reader import read_to_array
+
+    path, arr = multiband_tiff_path
+    out, _ = read_to_array(path, band=0)
+    np.testing.assert_array_equal(out, arr[:, :, 0])
+
+
+def test_read_to_array_band_one_still_works(multiband_tiff_path):
+    """``band=1`` is a plain int and still selects band 1."""
+    from xrspatial.geotiff._reader import read_to_array
+
+    path, arr = multiband_tiff_path
+    out, _ = read_to_array(path, band=1)
+    np.testing.assert_array_equal(out, arr[:, :, 1])
+
+
+# ---------------------------------------------------------------------------
+# open_geotiff (public dispatcher)
+# ---------------------------------------------------------------------------
+
+
+def test_open_geotiff_band_true_rejected(multiband_tiff_path):
+    """The public ``open_geotiff`` entry point rejects ``band=True``."""
+    from xrspatial.geotiff import open_geotiff
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        open_geotiff(path, band=True)
+
+
+def test_open_geotiff_band_false_rejected(multiband_tiff_path):
+    """``open_geotiff(..., band=False)`` is rejected the same way."""
+    from xrspatial.geotiff import open_geotiff
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        open_geotiff(path, band=False)
+
+
+# ---------------------------------------------------------------------------
+# read_geotiff_dask (dask CPU path)
+# ---------------------------------------------------------------------------
+
+
+def test_read_geotiff_dask_band_true_rejected(multiband_tiff_path):
+    """``read_geotiff_dask(..., band=True)`` is rejected before scheduling."""
+    from xrspatial.geotiff import read_geotiff_dask
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_geotiff_dask(path, chunks=4, band=True)
+
+
+def test_read_geotiff_dask_band_false_rejected(multiband_tiff_path):
+    """``read_geotiff_dask(..., band=False)`` raises the same way."""
+    from xrspatial.geotiff import read_geotiff_dask
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_geotiff_dask(path, chunks=4, band=False)
+
+
+# ---------------------------------------------------------------------------
+# read_geotiff_gpu (GPU path)
+# ---------------------------------------------------------------------------
+
+
+@_gpu_only
+def test_read_geotiff_gpu_band_true_rejected(multiband_tiff_path):
+    """``read_geotiff_gpu(..., band=True)`` is rejected (cupy required)."""
+    from xrspatial.geotiff import read_geotiff_gpu
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_geotiff_gpu(path, band=True)
+
+
+@_gpu_only
+def test_read_geotiff_gpu_band_false_rejected(multiband_tiff_path):
+    """``read_geotiff_gpu(..., band=False)`` raises the same way."""
+    from xrspatial.geotiff import read_geotiff_gpu
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_geotiff_gpu(path, band=False)
+
+
+# ---------------------------------------------------------------------------
+# read_vrt (regression: was already rejecting bool; should keep doing so)
+# ---------------------------------------------------------------------------
+
+
+def test_read_vrt_band_true_still_rejected(multiband_vrt_path):
+    """VRT path's existing bool rejection remains in place."""
+    from xrspatial.geotiff import read_vrt
+
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_vrt(multiband_vrt_path, band=True)
+
+
+def test_read_vrt_band_false_still_rejected(multiband_vrt_path):
+    """VRT path rejects ``band=False`` as well."""
+    from xrspatial.geotiff import read_vrt
+
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_vrt(multiband_vrt_path, band=False)
+
+
+# ---------------------------------------------------------------------------
+# np.bool_ parity: ``isinstance(np.bool_(True), bool)`` is False so it
+# bypasses a plain ``isinstance(band, bool)`` guard and is then treated
+# as 1/0 by the range check. The VRT path's
+# ``not isinstance(band, (int, np.integer))`` clause already rejects it;
+# every other read path must too so the four backends agree.
+# ---------------------------------------------------------------------------
+
+
+def test_read_to_array_band_np_bool_rejected(multiband_tiff_path):
+    """Local file path rejects ``band=np.bool_(True)``."""
+    from xrspatial.geotiff._reader import read_to_array
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_to_array(path, band=np.bool_(True))
+
+
+def test_open_geotiff_band_np_bool_rejected(multiband_tiff_path):
+    """``open_geotiff`` rejects ``band=np.bool_(False)``."""
+    from xrspatial.geotiff import open_geotiff
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        open_geotiff(path, band=np.bool_(False))
+
+
+def test_read_geotiff_dask_band_np_bool_rejected(multiband_tiff_path):
+    """``read_geotiff_dask`` rejects ``band=np.bool_(True)``."""
+    from xrspatial.geotiff import read_geotiff_dask
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_geotiff_dask(path, band=np.bool_(True))
+
+
+@_gpu_only
+def test_read_geotiff_gpu_band_np_bool_rejected(multiband_tiff_path):
+    """``read_geotiff_gpu`` rejects ``band=np.bool_(True)``."""
+    from xrspatial.geotiff import read_geotiff_gpu
+
+    path, _ = multiband_tiff_path
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_geotiff_gpu(path, band=np.bool_(True))
+
+
+def test_read_vrt_band_np_bool_still_rejected(multiband_vrt_path):
+    """VRT path already rejects ``np.bool_`` via its integer-type check."""
+    from xrspatial.geotiff import read_vrt
+
+    with pytest.raises(ValueError, match="band must be a non-negative int"):
+        read_vrt(multiband_vrt_path, band=np.bool_(True))