diff --git a/newsfragments/3036.fixed.md b/newsfragments/3036.fixed.md
new file mode 100644
index 00000000000..0c55f17ea69
--- /dev/null
+++ b/newsfragments/3036.fixed.md
@@ -0,0 +1 @@
+Correct FFI definitions `PyGetSetDef`, `PyMemberDef`, `PyStructSequence_Field` and `PyStructSequence_Desc` to have `*const c_char` members for `name` and `doc` (not `*mut c_char`).
diff --git a/pyo3-ffi/src/descrobject.rs b/pyo3-ffi/src/descrobject.rs
index b858497f9a4..c6f099b5923 100644
--- a/pyo3-ffi/src/descrobject.rs
+++ b/pyo3-ffi/src/descrobject.rs
@@ -11,7 +11,7 @@ pub type setter =
 #[repr(C)]
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub struct PyGetSetDef {
-    pub name: *mut c_char,
+    pub name: *const c_char,
     pub get: Option<getter>,
     pub set: Option<setter>,
     pub doc: *const c_char,
@@ -21,7 +21,7 @@ pub struct PyGetSetDef {
 impl Default for PyGetSetDef {
     fn default() -> PyGetSetDef {
         PyGetSetDef {
-            name: ptr::null_mut(),
+            name: ptr::null(),
             get: None,
             set: None,
             doc: ptr::null(),
diff --git a/pyo3-ffi/src/structmember.rs b/pyo3-ffi/src/structmember.rs
index b41cdaee412..81912042040 100644
--- a/pyo3-ffi/src/structmember.rs
+++ b/pyo3-ffi/src/structmember.rs
@@ -6,11 +6,11 @@ use std::ptr;
 #[repr(C)]
 #[derive(Copy, Clone, Eq, PartialEq)]
 pub struct PyMemberDef {
-    pub name: *mut c_char,
+    pub name: *const c_char,
     pub type_code: c_int,
     pub offset: Py_ssize_t,
     pub flags: c_int,
-    pub doc: *mut c_char,
+    pub doc: *const c_char,
 }
 
 impl Default for PyMemberDef {
diff --git a/pyo3-ffi/src/structseq.rs b/pyo3-ffi/src/structseq.rs
index 8e66a95e0e2..6dfc1daf158 100644
--- a/pyo3-ffi/src/structseq.rs
+++ b/pyo3-ffi/src/structseq.rs
@@ -6,15 +6,15 @@ use std::os::raw::{c_char, c_int};
 #[repr(C)]
 #[derive(Copy, Clone)]
 pub struct PyStructSequence_Field {
-    pub name: *mut c_char,
-    pub doc: *mut c_char,
+    pub name: *const c_char,
+    pub doc: *const c_char,
 }
 
 #[repr(C)]
 #[derive(Copy, Clone)]
 pub struct PyStructSequence_Desc {
-    pub name: *mut c_char,
-    pub doc: *mut c_char,
+    pub name: *const c_char,
+    pub doc: *const c_char,
     pub fields: *mut PyStructSequence_Field,
     pub n_in_sequence: c_int,
 }