diff --git a/include/nlohmann/ordered_map.hpp b/include/nlohmann/ordered_map.hpp
index bfcf89a40..4325a17b0 100644
--- a/include/nlohmann/ordered_map.hpp
+++ b/include/nlohmann/ordered_map.hpp
@@ -30,7 +30,8 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
 
     // Explicit constructors instead of `using Container::Container`
     // otherwise older compilers choke on it (GCC <= 5.5, xcode <= 9.4)
-    ordered_map(const Allocator& alloc = Allocator()) : Container{alloc} {}
+    ordered_map() noexcept(noexcept(Container())) : Container{} {}
+    explicit ordered_map(const Allocator& alloc) noexcept(noexcept(Container(alloc))) : Container{alloc} {}
     template <class It>
     ordered_map(It first, It last, const Allocator& alloc = Allocator())
         : Container{first, last, alloc} {}
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 00a5b0d22..fb2c44215 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -17066,7 +17066,8 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
 
     // Explicit constructors instead of `using Container::Container`
     // otherwise older compilers choke on it (GCC <= 5.5, xcode <= 9.4)
-    ordered_map(const Allocator& alloc = Allocator()) : Container{alloc} {}
+    ordered_map() noexcept(noexcept(Container())) : Container{} {}
+    explicit ordered_map(const Allocator& alloc) noexcept(noexcept(Container(alloc))) : Container{alloc} {}
     template <class It>
     ordered_map(It first, It last, const Allocator& alloc = Allocator())
         : Container{first, last, alloc} {}
diff --git a/test/src/unit-alt-string.cpp b/test/src/unit-alt-string.cpp
index 2c599a451..7da69dea1 100644
--- a/test/src/unit-alt-string.cpp
+++ b/test/src/unit-alt-string.cpp
@@ -104,12 +104,12 @@ class alt_string
     }
 
     template <typename op_type>
-    bool operator<(const op_type& op) const
+    bool operator<(const op_type& op) const noexcept
     {
         return str_impl < op;
     }
 
-    bool operator<(const alt_string& op) const
+    bool operator<(const alt_string& op) const noexcept
     {
         return str_impl < op.str_impl;
     }
diff --git a/test/src/unit-regression2.cpp b/test/src/unit-regression2.cpp
index 7c466b0b3..e7fe3443f 100644
--- a/test/src/unit-regression2.cpp
+++ b/test/src/unit-regression2.cpp
@@ -341,7 +341,7 @@ TEST_CASE("regression tests 2")
                ]
              })";
 
-        json::parser_callback_t cb = [&](int /*level*/, json::parse_event_t event, json & parsed)
+        json::parser_callback_t cb = [&](int /*level*/, json::parse_event_t event, json & parsed) noexcept
         {
             // skip uninteresting events
             if (event == json::parse_event_t::value && !parsed.is_primitive())