diff --git a/doc/source/whatsnew/v1.5.0.rst b/doc/source/whatsnew/v1.5.0.rst
index 74639cc693cb7..20c8dfae0de5e 100644
--- a/doc/source/whatsnew/v1.5.0.rst
+++ b/doc/source/whatsnew/v1.5.0.rst
@@ -342,6 +342,7 @@ Other Deprecations
 - Deprecated allowing non-keyword arguments in :meth:`ExtensionArray.argsort` (:issue:`46134`)
 - Deprecated treating all-bool ``object``-dtype columns as bool-like in :meth:`DataFrame.any` and :meth:`DataFrame.all` with ``bool_only=True``, explicitly cast to bool instead (:issue:`46188`)
 - Deprecated behavior of method :meth:`DataFrame.quantile`, attribute ``numeric_only`` will default False. Including datetime/timedelta columns in the result (:issue:`7308`).
+- Deprecated :attr:`Timedelta.freq` and :attr:`Timedelta.is_populated` (:issue:`46430`)
 -
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/_libs/tslibs/timedeltas.pxd b/pandas/_libs/tslibs/timedeltas.pxd
index fed1f2d326819..f054a22ed7ad7 100644
--- a/pandas/_libs/tslibs/timedeltas.pxd
+++ b/pandas/_libs/tslibs/timedeltas.pxd
@@ -11,8 +11,7 @@ cdef bint is_any_td_scalar(object obj)
 cdef class _Timedelta(timedelta):
     cdef readonly:
         int64_t value      # nanoseconds
-        object freq        # frequency reference
-        bint is_populated  # are my components populated
+        bint _is_populated  # are my components populated
         int64_t _d, _h, _m, _s, _ms, _us, _ns
 
     cpdef timedelta to_pytimedelta(_Timedelta self)
diff --git a/pandas/_libs/tslibs/timedeltas.pyi b/pandas/_libs/tslibs/timedeltas.pyi
index 28c2f7db62158..f4711f728907d 100644
--- a/pandas/_libs/tslibs/timedeltas.pyi
+++ b/pandas/_libs/tslibs/timedeltas.pyi
@@ -146,3 +146,7 @@ class Timedelta(timedelta):
     def __hash__(self) -> int: ...
     def isoformat(self) -> str: ...
     def to_numpy(self) -> np.timedelta64: ...
+    @property
+    def freq(self) -> None: ...
+    @property
+    def is_populated(self) -> bool: ...
diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index 6b7ebf96633b3..5df316f86dd02 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -826,13 +826,32 @@ cdef _to_py_int_float(v):
 cdef class _Timedelta(timedelta):
     # cdef readonly:
     #    int64_t value      # nanoseconds
-    #    object freq        # frequency reference
-    #    bint is_populated  # are my components populated
+    #    bint _is_populated  # are my components populated
     #    int64_t _d, _h, _m, _s, _ms, _us, _ns
 
     # higher than np.ndarray and np.matrix
     __array_priority__ = 100
 
+    @property
+    def freq(self) -> None:
+        # GH#46430
+        warnings.warn(
+            "Timedelta.freq is deprecated and will be removed in a future version",
+            FutureWarning,
+            stacklevel=1,
+        )
+        return None
+
+    @property
+    def is_populated(self) -> bool:
+        # GH#46430
+        warnings.warn(
+            "Timedelta.is_populated is deprecated and will be removed in a future version",
+            FutureWarning,
+            stacklevel=1,
+        )
+        return self._is_populated
+
     def __hash__(_Timedelta self):
         if self._has_ns():
             return hash(self.value)
@@ -881,7 +900,7 @@ cdef class _Timedelta(timedelta):
         """
         compute the components
         """
-        if self.is_populated:
+        if self._is_populated:
             return
 
         cdef:
@@ -898,7 +917,7 @@ cdef class _Timedelta(timedelta):
         self._seconds = tds.seconds
         self._microseconds = tds.microseconds
 
-        self.is_populated = 1
+        self._is_populated = 1
 
     cpdef timedelta to_pytimedelta(_Timedelta self):
         """
@@ -1389,7 +1408,7 @@ class Timedelta(_Timedelta):
         # make timedelta happy
         td_base = _Timedelta.__new__(cls, microseconds=int(value) // 1000)
         td_base.value = value
-        td_base.is_populated = 0
+        td_base._is_populated = 0
         return td_base
 
     def __setstate__(self, state):
diff --git a/pandas/tests/scalar/timedelta/test_timedelta.py b/pandas/tests/scalar/timedelta/test_timedelta.py
index 7a32c932aee77..36520a1983aac 100644
--- a/pandas/tests/scalar/timedelta/test_timedelta.py
+++ b/pandas/tests/scalar/timedelta/test_timedelta.py
@@ -659,3 +659,25 @@ def test_timedelta_attribute_precision():
     result += td.nanoseconds
     expected = td.value
     assert result == expected
+
+
+def test_freq_deprecated():
+    # GH#46430
+    td = Timedelta(123456546, unit="ns")
+    with tm.assert_produces_warning(FutureWarning, match="Timedelta.freq"):
+        freq = td.freq
+
+    assert freq is None
+
+    with pytest.raises(AttributeError, match="is not writable"):
+        td.freq = offsets.Day()
+
+
+def test_is_populated_deprecated():
+    # GH#46430
+    td = Timedelta(123456546, unit="ns")
+    with tm.assert_produces_warning(FutureWarning, match="Timedelta.is_populated"):
+        td.is_populated
+
+    with pytest.raises(AttributeError, match="is not writable"):
+        td.is_populated = 1