diff --git a/include/gsl/span b/include/gsl/span
index 51b46f2..76f16e1 100644
--- a/include/gsl/span
+++ b/include/gsl/span
@@ -389,7 +389,6 @@ public:
     }
 
     constexpr span(const span& other) GSL_NOEXCEPT = default;
-    constexpr span(span&& other) GSL_NOEXCEPT = default;
 
     template <
         class OtherElementType, std::ptrdiff_t OtherExtent,
@@ -401,21 +400,9 @@ public:
     {
     }
 
-    template <
-        class OtherElementType, std::ptrdiff_t OtherExtent,
-        class = std::enable_if_t<
-            details::is_allowed_extent_conversion<OtherExtent, Extent>::value &&
-            details::is_allowed_element_type_conversion<OtherElementType, element_type>::value>>
-    constexpr span(span<OtherElementType, OtherExtent>&& other)
-        : storage_(other.data(), details::extent_type<OtherExtent>(other.size()))
-    {
-    }
-
     ~span() GSL_NOEXCEPT = default;
     constexpr span& operator=(const span& other) GSL_NOEXCEPT = default;
-
-    constexpr span& operator=(span&& other) GSL_NOEXCEPT = default;
-
+    
     // [span.sub], span subviews
     template <std::ptrdiff_t Count>
     constexpr span<element_type, Count> first() const
diff --git a/include/gsl/string_span b/include/gsl/string_span
index 0c9f2cf..cd9ddf9 100644
--- a/include/gsl/string_span
+++ b/include/gsl/string_span
@@ -194,15 +194,9 @@ public:
     // copy
     constexpr basic_string_span(const basic_string_span& other) GSL_NOEXCEPT = default;
 
-    // move
-    constexpr basic_string_span(basic_string_span&& other) GSL_NOEXCEPT = default;
-
     // assign
     constexpr basic_string_span& operator=(const basic_string_span& other) GSL_NOEXCEPT = default;
 
-    // move assign
-    constexpr basic_string_span& operator=(basic_string_span&& other) GSL_NOEXCEPT = default;
-
     constexpr basic_string_span(pointer ptr, index_type length) : span_(ptr, length) {}
     constexpr basic_string_span(pointer firstElem, pointer lastElem) : span_(firstElem, lastElem) {}