diff --git a/prost-derive/src/field/group.rs b/prost-derive/src/field/group.rs
index 639612880..076b577d7 100644
--- a/prost-derive/src/field/group.rs
+++ b/prost-derive/src/field/group.rs
@@ -95,7 +95,7 @@ impl Field {
                 ::prost::encoding::group::merge(
                     tag,
                     wire_type,
-                    #ident.get_or_insert_with(Default::default),
+                    #ident.get_or_insert_with(::core::default::Default::default),
                     buf,
                     ctx,
                 )
diff --git a/prost-derive/src/field/message.rs b/prost-derive/src/field/message.rs
index 1ff7c3798..3bcdddfb1 100644
--- a/prost-derive/src/field/message.rs
+++ b/prost-derive/src/field/message.rs
@@ -96,7 +96,7 @@ impl Field {
         match self.label {
             Label::Optional => quote! {
                 ::prost::encoding::message::merge(wire_type,
-                                                 #ident.get_or_insert_with(Default::default),
+                                                 #ident.get_or_insert_with(::core::default::Default::default),
                                                  buf,
                                                  ctx)
             },
diff --git a/prost-derive/src/field/scalar.rs b/prost-derive/src/field/scalar.rs
index 75a4fe3a8..35f249353 100644
--- a/prost-derive/src/field/scalar.rs
+++ b/prost-derive/src/field/scalar.rs
@@ -151,7 +151,7 @@ impl Field {
             },
             Kind::Optional(..) => quote! {
                 #merge_fn(wire_type,
-                          #ident.get_or_insert_with(Default::default),
+                          #ident.get_or_insert_with(::core::default::Default::default),
                           buf,
                           ctx)
             },
@@ -769,7 +769,9 @@ impl DefaultValue {
                 quote!(::prost::alloc::string::String::new())
             }
             DefaultValue::String(ref value) => quote!(#value.into()),
-            DefaultValue::Bytes(ref value) if value.is_empty() => quote!(Default::default()),
+            DefaultValue::Bytes(ref value) if value.is_empty() => {
+                quote!(::core::default::Default::default())
+            }
             DefaultValue::Bytes(ref value) => {
                 let lit = LitByteStr::new(value, Span::call_site());
                 quote!(#lit.as_ref().into())
diff --git a/prost-derive/src/lib.rs b/prost-derive/src/lib.rs
index a517c41e8..3cc23a533 100644
--- a/prost-derive/src/lib.rs
+++ b/prost-derive/src/lib.rs
@@ -204,7 +204,7 @@ fn try_message(input: TokenStream) -> Result<TokenStream, Error> {
             }
         }
 
-        impl #impl_generics Default for #ident #ty_generics #where_clause {
+        impl #impl_generics ::core::default::Default for #ident #ty_generics #where_clause {
             fn default() -> Self {
                 #ident {
                     #(#default)*