diff --git a/modules/core/include/opencv2/core/mat.hpp b/modules/core/include/opencv2/core/mat.hpp
index 718d15abb9..84df297bf9 100644
--- a/modules/core/include/opencv2/core/mat.hpp
+++ b/modules/core/include/opencv2/core/mat.hpp
@@ -576,24 +576,24 @@ CV_ENUM_FLAGS(UMatData::MemoryFlag)
 
 struct CV_EXPORTS MatSize
 {
-    explicit MatSize(int* _p);
-    int dims() const;
+    explicit MatSize(int* _p) CV_NOEXCEPT;
+    int dims() const CV_NOEXCEPT;
     Size operator()() const;
     const int& operator[](int i) const;
     int& operator[](int i);
-    operator const int*() const;  // TODO OpenCV 4.0: drop this
-    bool operator == (const MatSize& sz) const;
-    bool operator != (const MatSize& sz) const;
+    operator const int*() const CV_NOEXCEPT;  // TODO OpenCV 4.0: drop this
+    bool operator == (const MatSize& sz) const CV_NOEXCEPT;
+    bool operator != (const MatSize& sz) const CV_NOEXCEPT;
 
     int* p;
 };
 
 struct CV_EXPORTS MatStep
 {
-    MatStep();
-    explicit MatStep(size_t s);
-    const size_t& operator[](int i) const;
-    size_t& operator[](int i);
+    MatStep() CV_NOEXCEPT;
+    explicit MatStep(size_t s) CV_NOEXCEPT;
+    const size_t& operator[](int i) const CV_NOEXCEPT;
+    size_t& operator[](int i) CV_NOEXCEPT;
     operator size_t() const;
     MatStep& operator = (size_t s);
 
@@ -807,7 +807,7 @@ public:
     The constructed matrix can further be assigned to another matrix or matrix expression or can be
     allocated with Mat::create . In the former case, the old content is de-referenced.
      */
-    Mat();
+    Mat() CV_NOEXCEPT;
 
     /** @overload
     @param rows Number of rows in a 2D array.
@@ -2193,7 +2193,7 @@ public:
     typedef MatConstIterator_<_Tp> const_iterator;
 
     //! default constructor
-    Mat_();
+    Mat_() CV_NOEXCEPT;
     //! equivalent to Mat(_rows, _cols, DataType<_Tp>::type)
     Mat_(int _rows, int _cols);
     //! constructor that sets each matrix element to specified value
@@ -2385,7 +2385,7 @@ class CV_EXPORTS UMat
 {
 public:
     //! default constructor
-    UMat(UMatUsageFlags usageFlags = USAGE_DEFAULT);
+    UMat(UMatUsageFlags usageFlags = USAGE_DEFAULT) CV_NOEXCEPT;
     //! constructs 2D matrix of the specified size and type
     // (_type is CV_8UC1, CV_64FC3, CV_32SC(12) etc.)
     UMat(int rows, int cols, int type, UMatUsageFlags usageFlags = USAGE_DEFAULT);
diff --git a/modules/core/include/opencv2/core/mat.inl.hpp b/modules/core/include/opencv2/core/mat.inl.hpp
index c51d8fea4a..ff8297ffa4 100644
--- a/modules/core/include/opencv2/core/mat.inl.hpp
+++ b/modules/core/include/opencv2/core/mat.inl.hpp
@@ -1116,11 +1116,11 @@ void Mat::push_back(const std::vector<_Tp>& v)
 ///////////////////////////// MatSize ////////////////////////////
 
 inline
-MatSize::MatSize(int* _p)
+MatSize::MatSize(int* _p) CV_NOEXCEPT
     : p(_p) {}
 
 inline
-int MatSize::dims() const
+int MatSize::dims() const CV_NOEXCEPT
 {
     return (p - 1)[0];
 }
@@ -1153,13 +1153,13 @@ int& MatSize::operator[](int i)
 }
 
 inline
-MatSize::operator const int*() const
+MatSize::operator const int*() const CV_NOEXCEPT
 {
     return p;
 }
 
 inline
-bool MatSize::operator != (const MatSize& sz) const
+bool MatSize::operator != (const MatSize& sz) const CV_NOEXCEPT
 {
     return !(*this == sz);
 }
@@ -1169,25 +1169,25 @@ bool MatSize::operator != (const MatSize& sz) const
 ///////////////////////////// MatStep ////////////////////////////
 
 inline
-MatStep::MatStep()
+MatStep::MatStep() CV_NOEXCEPT
 {
     p = buf; p[0] = p[1] = 0;
 }
 
 inline
-MatStep::MatStep(size_t s)
+MatStep::MatStep(size_t s) CV_NOEXCEPT
 {
     p = buf; p[0] = s; p[1] = 0;
 }
 
 inline
-const size_t& MatStep::operator[](int i) const
+const size_t& MatStep::operator[](int i) const CV_NOEXCEPT
 {
     return p[i];
 }
 
 inline
-size_t& MatStep::operator[](int i)
+size_t& MatStep::operator[](int i) CV_NOEXCEPT
 {
     return p[i];
 }
@@ -1210,7 +1210,7 @@ inline MatStep& MatStep::operator = (size_t s)
 ////////////////////////////// Mat_<_Tp> ////////////////////////////
 
 template<typename _Tp> inline
-Mat_<_Tp>::Mat_()
+Mat_<_Tp>::Mat_() CV_NOEXCEPT
     : Mat()
 {
     flags = (flags & ~CV_MAT_TYPE_MASK) + traits::Type<_Tp>::value;
diff --git a/modules/core/src/matrix.cpp b/modules/core/src/matrix.cpp
index 122b383379..61abc2ba8f 100644
--- a/modules/core/src/matrix.cpp
+++ b/modules/core/src/matrix.cpp
@@ -204,7 +204,7 @@ MatAllocator* Mat::getStdAllocator()
 
 //==================================================================================================
 
-bool MatSize::operator==(const MatSize& sz) const
+bool MatSize::operator==(const MatSize& sz) const CV_NOEXCEPT
 {
     int d = dims();
     int dsz = sz.dims();
@@ -337,7 +337,7 @@ void finalizeHdr(Mat& m)
 
 //======================================= Mat ======================================================
 
-Mat::Mat()
+Mat::Mat() CV_NOEXCEPT
     : flags(MAGIC_VAL), dims(0), rows(0), cols(0), data(0), datastart(0), dataend(0),
       datalimit(0), allocator(0), u(0), size(&rows), step(0)
 {}
diff --git a/modules/core/src/umatrix.cpp b/modules/core/src/umatrix.cpp
index 14d73ca14e..09ba92ecde 100644
--- a/modules/core/src/umatrix.cpp
+++ b/modules/core/src/umatrix.cpp
@@ -230,7 +230,7 @@ UMatDataAutoLock::~UMatDataAutoLock()
 
 //////////////////////////////// UMat ////////////////////////////////
 
-UMat::UMat(UMatUsageFlags _usageFlags)
+UMat::UMat(UMatUsageFlags _usageFlags) CV_NOEXCEPT
 : flags(MAGIC_VAL), dims(0), rows(0), cols(0), allocator(0), usageFlags(_usageFlags), u(0), offset(0), size(&rows)
 {}