diff --git a/graphicle/data.py b/graphicle/data.py
index abd9f71..2cbc334 100644
--- a/graphicle/data.py
+++ b/graphicle/data.py
@@ -642,7 +642,9 @@ def _mask_neq(mask1: base.MaskLike, mask2: base.MaskLike) -> MaskArray:
     return MaskArray(np.not_equal(mask1, mask2))
 
 
-_IN_MASK_DICT = ty.OrderedDict[str, ty.Union[MaskArray, base.BoolVector]]
+_IN_MASK_DICT = ty.Mapping[
+    str, ty.Union[MaskArray, base.BoolVector, ty.Iterable[bool]]
+]
 _MASK_DICT = ty.OrderedDict[str, MaskArray]
 
 
@@ -651,12 +653,32 @@ def _mask_dict_convert(masks: _IN_MASK_DICT) -> _MASK_DICT:
     for key, val in masks.items():
         if isinstance(val, MaskArray) or isinstance(val, MaskGroup):
             mask = val
+        elif isinstance(val, cla.Mapping):
+            mask = MaskGroup(_mask_dict_convert(val))
         else:
             mask = MaskArray(val)
         out_masks[key] = mask
     return out_masks
 
 
+def _maskgroup_equal(
+    group_1: "MaskGroup", group_2: "MaskGroup", check_order: bool
+) -> bool:
+    key_struct = tuple if check_order else set
+    if key_struct(group_1) != key_struct(group_2):
+        return False
+    for key in group_1:
+        mask_1, mask_2 = group_1[key], group_2[key]
+        if type(mask_1) != type(mask_2):
+            return False
+        if isinstance(mask_1, MaskGroup):
+            if not _maskgroup_equal(mask_1, mask_2, check_order):
+                return False
+        elif not np.array_equal(mask_1.data, mask_2.data):
+            return False
+    return True
+
+
 class MaskAggOp(Enum):
     AND = "and"
     OR = "or"
@@ -980,6 +1002,29 @@ def serialize(self) -> ty.Dict[str, ty.Any]:
         """
         return {key: val.serialize() for key, val in self._mask_arrays.items()}
 
+    def equal_to(self, other: "MaskGroup", check_order: bool = False) -> bool:
+        """Checks whether this instance is identical to ``other``
+        ``MaskGroup``, comparing keys at all levels of nesting, and
+        boolean array data at the leaf level.
+
+        .. versionadded:: 0.3.9
+
+        Parameters
+        ----------
+        other : MaskGroup
+            Other instance, against which to compare for equality.
+        check_order : bool
+            If ``True``, will check that the ordering of elements is
+            identical. Default is ``False``.
+
+        Returns
+        -------
+        bool
+            ``True`` if instance is identical to ``other``, ``False``
+            otherwise.
+        """
+        return _maskgroup_equal(self, other, check_order)
+
 
 @define(eq=False)
 class PdgArray(base.ArrayBase):
diff --git a/tests/test_data.py b/tests/test_data.py
index 07f7943..fce7859 100644
--- a/tests/test_data.py
+++ b/tests/test_data.py
@@ -9,6 +9,7 @@
 import dataclasses as dc
 import math
 import random
+import string
 
 import numpy as np
 import pytest
@@ -18,6 +19,13 @@
 ZERO_TOL = 1.0e-10  # absolute tolerance for detecting zero-values
 
 
+def random_alphanum(length: int) -> str:
+    return "".join(
+        random.choice(string.ascii_letters + string.digits)
+        for _ in range(length)
+    )
+
+
 @dc.dataclass
 class MomentumExample:
     """Dataclass for representing the four-momentum of a particle, based
@@ -111,3 +119,57 @@ def test_pmu_zero_pt() -> None:
     with pytest.warns(gcl.base.NumericalStabilityWarning):
         phi_invalid = math.isnan(pmu_zero_pt.phi.item())
     assert phi_invalid, "Azimuth is not NaN when pT is low"
+
+
+def generate_tree(
+    max_width: int, max_depth: int, leaf_length: int
+) -> gcl.MaskGroup:
+    """Generates a nested MaskGroup tree structure, with random branch
+    widths and depths.
+
+    Parameters
+    ----------
+    max_width, max_depth : int
+        Maximum limits on the nested tree structure.
+    leaf_length : int
+        The number of elements in the leaf MaskArrays.
+
+    Returns
+    -------
+    MaskGroup
+        Tree structure, with random structure, and random MaskArrays at
+        the leaf levels.
+    """
+    rng = np.random.default_rng()
+
+    def generate_branch(depth: int) -> gcl.base.MaskBase:
+        if (depth == 0) or (
+            random.choice((True, False)) and not (depth == max_depth)
+        ):
+            return gcl.MaskArray(
+                rng.integers(0, 2, size=leaf_length, dtype=np.bool_)
+            )
+        num_children = random.randint(1, max_width)
+        return gcl.MaskGroup(
+            {
+                random_alphanum(10): generate_branch(depth - 1)
+                for _ in range(num_children)
+            }
+        )
+
+    return generate_branch(max_depth)
+
+
+def test_maskgroup_serialize_inverse() -> None:
+    """Tests that instantiating a MaskGroup from its serialization
+    yields identical results to the original.
+    """
+    invertible = True
+    for _ in range(10):
+        maskgroup = generate_tree(
+            max_width=5,
+            max_depth=10,
+            leaf_length=random.randint(0, 1_000),
+        )
+        invertible &= maskgroup.equal_to(gcl.MaskGroup(maskgroup.serialize()))
+    assert invertible, "Serializing MaskGroups is not invertible."