diff --git a/cpp/src/arrow/python/numpy_convert.cc b/cpp/src/arrow/python/numpy_convert.cc
index 515864ae287..30e61985027 100644
--- a/cpp/src/arrow/python/numpy_convert.cc
+++ b/cpp/src/arrow/python/numpy_convert.cc
@@ -37,15 +37,6 @@
 namespace arrow {
 namespace py {
 
-bool is_contiguous(PyObject* array) {
-  if (PyArray_Check(array)) {
-    return (PyArray_FLAGS(reinterpret_cast<PyArrayObject*>(array)) &
-            (NPY_ARRAY_C_CONTIGUOUS | NPY_ARRAY_F_CONTIGUOUS)) != 0;
-  } else {
-    return false;
-  }
-}
-
 NumPyBuffer::NumPyBuffer(PyObject* ao) : Buffer(nullptr, 0) {
   PyAcquireGIL lock;
   arr_ = ao;
@@ -73,6 +64,8 @@ NumPyBuffer::~NumPyBuffer() {
     *out = FACTORY();                         \
     break;
 
+namespace {
+
 Status GetTensorType(PyObject* dtype, std::shared_ptr<DataType>* out) {
   if (!PyArray_DescrCheck(dtype)) {
     return Status::TypeError("Did not pass numpy.dtype object");
@@ -127,6 +120,8 @@ Status GetNumPyType(const DataType& type, int* type_num) {
   return Status::OK();
 }
 
+}  // namespace
+
 Status NumPyDtypeToArrow(PyObject* dtype, std::shared_ptr<DataType>* out) {
   if (!PyArray_DescrCheck(dtype)) {
     return Status::TypeError("Did not pass numpy.dtype object");
diff --git a/cpp/src/arrow/python/numpy_convert.h b/cpp/src/arrow/python/numpy_convert.h
index 5fa1326f52b..85ef36b1bc5 100644
--- a/cpp/src/arrow/python/numpy_convert.h
+++ b/cpp/src/arrow/python/numpy_convert.h
@@ -49,21 +49,11 @@ class ARROW_PYTHON_EXPORT NumPyBuffer : public Buffer {
   PyObject* arr_;
 };
 
-// Handle misbehaved types like LONGLONG and ULONGLONG
-ARROW_PYTHON_EXPORT
-int cast_npy_type_compat(int type_num);
-
-ARROW_PYTHON_EXPORT
-bool is_contiguous(PyObject* array);
-
 ARROW_PYTHON_EXPORT
 Status NumPyDtypeToArrow(PyObject* dtype, std::shared_ptr<DataType>* out);
 ARROW_PYTHON_EXPORT
 Status NumPyDtypeToArrow(PyArray_Descr* descr, std::shared_ptr<DataType>* out);
 
-Status GetTensorType(PyObject* dtype, std::shared_ptr<DataType>* out);
-Status GetNumPyType(const DataType& type, int* type_num);
-
 ARROW_PYTHON_EXPORT Status NdarrayToTensor(MemoryPool* pool, PyObject* ao,
                                            const std::vector<std::string>& dim_names,
                                            std::shared_ptr<Tensor>* out);