diff --git a/scipy-stubs/signal/_polyutils.pyi b/scipy-stubs/signal/_polyutils.pyi
new file mode 100644
index 00000000..6dec88a6
--- /dev/null
+++ b/scipy-stubs/signal/_polyutils.pyi
@@ -0,0 +1,24 @@
+from types import ModuleType
+from typing import Any, TypeVar
+
+import numpy as np
+import optype.numpy as onp
+import optype.numpy.compat as npc
+
+_InexactT = TypeVar("_InexactT", bound=npc.inexact)
+
+###
+
+def _sort_cmplx(arr: onp.ArrayND[_InexactT], xp: ModuleType) -> onp.ArrayND[_InexactT]: ...
+def polyroots(coef: onp.ArrayND[_InexactT], *, xp: ModuleType) -> onp.ArrayND[_InexactT]: ...
+def _trim_zeros(filt: onp.Array1D[_InexactT], trim: str = "fb") -> onp.Array1D[_InexactT]: ...
+def _poly1d(c_or_r: onp.Array1D[_InexactT], *, xp: ModuleType) -> onp.Array1D[_InexactT]: ...
+def polyval(p: onp.ArrayND[npc.number], x: onp.ArrayND[_InexactT], *, xp: ModuleType) -> onp.ArrayND[_InexactT]: ...
+def poly(seq_of_zeros: onp.ToComplex1D, *, xp: ModuleType) -> onp.ArrayND[np.float64 | Any]: ...
+def polymul(a1: onp.ArrayND[_InexactT], a2: onp.ArrayND[_InexactT], *, xp: ModuleType) -> onp.ArrayND[_InexactT]: ...
+def npp_polyval(
+    x: onp.ToComplex | onp.ToComplexND, c: onp.ArrayND[npc.number], *, xp: ModuleType, tensor: bool = True
+) -> onp.ArrayND[np.float64 | Any]: ...
+def npp_polyvalfromroots(
+    x: onp.ToComplex | onp.ToComplexND, r: onp.ArrayND[npc.number], *, xp: ModuleType, tensor: bool = True
+) -> onp.ArrayND[np.float64 | Any]: ...
diff --git a/scipy-stubs/signal/_sigtools.pyi b/scipy-stubs/signal/_sigtools.pyi
new file mode 100644
index 00000000..8ce3e3d5
--- /dev/null
+++ b/scipy-stubs/signal/_sigtools.pyi
@@ -0,0 +1,52 @@
+from _typeshed import Incomplete
+from typing import Literal, TypeAlias, TypeVar
+
+import numpy as np
+import optype.numpy as onp
+import optype.numpy.compat as npc
+
+_NumberT = TypeVar("_NumberT", bound=npc.number)
+_ImageScalarT = TypeVar("_ImageScalarT", bound=np.uint8 | np.float32 | np.float64)
+_Mode: TypeAlias = Literal[0, 1, 2]
+
+###
+
+# defined in scipy/signal/_correlate_nd.cc
+def _correlateND(
+    x: onp.ArrayND[_NumberT], y: onp.ArrayND[_NumberT], out: onp.ArrayND[_NumberT], mode: _Mode = 2
+) -> onp.ArrayND[_NumberT]: ...
+
+# defined in scipy/signal/_sigtoolsmodule.cc
+def _convolve2d(
+    in1: onp.ArrayND[_NumberT],
+    in2: onp.ArrayND[_NumberT],
+    flip: int = 1,
+    mode: _Mode = 2,
+    boundary: int = 0,
+    fillvalue: Incomplete | None = None,
+) -> Incomplete: ...
+
+# defined in scipy/signal/_lfilter.cc
+def _linear_filter(
+    b: onp.ArrayND[_NumberT],
+    a: onp.ArrayND[_NumberT],
+    X: onp.ArrayND[_NumberT],
+    axis: int = -1,
+    Vi: onp.ArrayND[_NumberT] | None = None,
+) -> onp.ArrayND[_NumberT]: ...
+
+# defined in scipy/signal/_sigtoolsmodule.cc
+def _remez(
+    numtaps: int,
+    bands: onp.ArrayND[np.float64],
+    des: onp.ArrayND[np.float64],
+    weight: onp.ArrayND[np.float64],
+    type: Literal[1, 2, 3] = 1,
+    fs: float = 1.0,
+    maxiter: int = 25,
+    grid_density: int = 16,
+) -> onp.ArrayND[np.float64]: ...
+
+#
+# defined in scipy/signal/_sigtoolsmodule.cc
+def _medfilt2d(image: onp.Array2D[_ImageScalarT], size: tuple[int, int]) -> onp.Array2D[_ImageScalarT]: ...
diff --git a/scipy-stubs/signal/_sosfilt.pyi b/scipy-stubs/signal/_sosfilt.pyi
new file mode 100644
index 00000000..4b57365e
--- /dev/null
+++ b/scipy-stubs/signal/_sosfilt.pyi
@@ -0,0 +1,14 @@
+# defined in scipy/signal/_sosfilt.pyx
+
+from typing import TypeVar
+
+import numpy as np
+import optype.numpy as onp
+
+# emulate `ctypedef fused DTYPE_t`
+_DTypeT = TypeVar("_DTypeT", np.float32, np.float64, np.longdouble, np.complex64, np.complex128, np.clongdouble, np.object_)
+
+###
+
+def _sosfilt_object(sos: onp.Array2D[np.object_], x: onp.Array2D[np.object_], zi: onp.Array3D[np.object_]) -> None: ...
+def _sosfilt(sos: onp.Array2D[_DTypeT], x: onp.Array2D[_DTypeT], zi: onp.Array3D[_DTypeT]) -> None: ...
diff --git a/scipy-stubs/signal/_upfirdn_apply.pyi b/scipy-stubs/signal/_upfirdn_apply.pyi
new file mode 100644
index 00000000..1e3b517b
--- /dev/null
+++ b/scipy-stubs/signal/_upfirdn_apply.pyi
@@ -0,0 +1,30 @@
+# defined in scipy/signal/_upfirdn_apply.pyx
+
+from typing import Literal, TypeAlias, TypeVar
+
+import numpy as np
+import optype.numpy as onp
+import optype.numpy.compat as npc
+
+_DTypeT = TypeVar("_DTypeT", np.float32, np.float64, np.complex64, np.complex128)
+
+_Mode: TypeAlias = Literal["constant", "symmetric", "edge", "smooth", "wrap", "reflect", "antisymmetric", "antireflect", "line"]
+_ModeCode: TypeAlias = Literal[0, 1, 2, 3, 4, 5, 6, 7, 8]
+
+###
+
+def _output_len(len_h: np.int64 | int, in_len: np.int64 | int, up: np.int64 | int, down: np.int64 | int) -> int: ...
+def mode_enum(mode: _Mode) -> _ModeCode: ...
+def _pad_test(
+    data: onp.ArrayND[_DTypeT], npre: np.intp | int = 0, npost: np.intp | int = 0, mode: _ModeCode = 0
+) -> onp.Array1D[_DTypeT]: ...
+def _apply(
+    data: onp.ArrayND[npc.number],
+    h_trans_flip: onp.Array1D[_DTypeT],
+    out: onp.ArrayND[npc.number],
+    up: np.intp | int,
+    down: np.intp | int,
+    axis: np.intp | int,
+    mode: np.intp | int,
+    cval: _DTypeT | complex,
+) -> onp.ArrayND[_DTypeT]: ...