diff --git a/Cargo.lock b/Cargo.lock
index 864e90ce5a..274daba698 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -827,6 +827,7 @@ dependencies = [
  "serde_derive 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "statrs 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-casing 0.1.0 (git+https://github.com/OddCoincidence/unicode-casing?rev=90d6d1f02b9cc04ffb55a5f1c3fa1455a84231fb)",
  "unicode-segmentation 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1102,6 +1103,11 @@ dependencies = [
  "unic-common 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "unicode-casing"
+version = "0.1.0"
+source = "git+https://github.com/OddCoincidence/unicode-casing?rev=90d6d1f02b9cc04ffb55a5f1c3fa1455a84231fb#90d6d1f02b9cc04ffb55a5f1c3fa1455a84231fb"
+
 [[package]]
 name = "unicode-normalization"
 version = "0.1.8"
@@ -1431,6 +1437,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum unic-common 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "80d7ff825a6a654ee85a63e80f92f054f904f21e7d12da4e22f9834a4aaa35bc"
 "checksum unic-emoji-char 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0b07221e68897210270a38bde4babb655869637af0f69407f96053a34f76494d"
 "checksum unic-ucd-version 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "96bd2f2237fe450fcd0a1d2f5f4e91711124f7857ba2e964247776ebeeb7b0c4"
+"checksum unicode-casing 0.1.0 (git+https://github.com/OddCoincidence/unicode-casing?rev=90d6d1f02b9cc04ffb55a5f1c3fa1455a84231fb)" = "<none>"
 "checksum unicode-normalization 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "141339a08b982d942be2ca06ff8b076563cbe223d1befd5450716790d44e2426"
 "checksum unicode-segmentation 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "aa6024fc12ddfd1c6dbc14a80fa2324d4568849869b779f6bd37e5e4c03344d1"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
index ef1a9cbc35..5af648084a 100644
--- a/vm/Cargo.toml
+++ b/vm/Cargo.toml
@@ -27,3 +27,8 @@ unicode-segmentation = "1.2.1"
 lazy_static = "^1.0.1"
 lexical = "2.0.0"
 itertools = "^0.8.0"
+
+# TODO: release and publish to crates.io
+[dependencies.unicode-casing]
+git = "https://github.com/OddCoincidence/unicode-casing"
+rev = "90d6d1f02b9cc04ffb55a5f1c3fa1455a84231fb"
diff --git a/vm/src/obj/objstr.rs b/vm/src/obj/objstr.rs
index 1638a712ce..b52a91409d 100644
--- a/vm/src/obj/objstr.rs
+++ b/vm/src/obj/objstr.rs
@@ -5,6 +5,7 @@ use std::str::FromStr;
 use std::string::ToString;
 
 use num_traits::ToPrimitive;
+use unicode_casing::CharExt;
 use unicode_segmentation::UnicodeSegmentation;
 
 use crate::format::{FormatParseError, FormatPart, FormatString};
@@ -413,12 +414,12 @@ impl PyString {
         for c in self.value.chars() {
             if c.is_lowercase() {
                 if !previous_is_cased {
-                    title.extend(c.to_uppercase());
+                    title.extend(c.to_titlecase());
                 } else {
                     title.push(c);
                 }
                 previous_is_cased = true;
-            } else if c.is_uppercase() {
+            } else if c.is_uppercase() || c.is_titlecase() {
                 if previous_is_cased {
                     title.extend(c.to_lowercase());
                 } else {
@@ -652,7 +653,7 @@ impl PyString {
         let mut cased = false;
         let mut previous_is_cased = false;
         for c in self.value.chars() {
-            if c.is_uppercase() {
+            if c.is_uppercase() || c.is_titlecase() {
                 if previous_is_cased {
                     return false;
                 }
@@ -1050,6 +1051,7 @@ mod tests {
             ("Format,This-As*Title;String", "fOrMaT,thIs-aS*titLe;String"),
             ("Getint", "getInt"),
             ("Greek Ωppercases ...", "greek ωppercases ..."),
+            ("Greek ῼitlecases ...", "greek ῳitlecases ..."),
         ];
         for (title, input) in tests {
             assert_eq!(PyString::from(input).title(&vm).as_str(), title);
@@ -1066,6 +1068,7 @@ mod tests {
             "A\nTitlecased Line",
             "A Titlecased, Line",
             "Greek Ωppercases ...",
+            "Greek ῼitlecases ...",
         ];
 
         for s in pos {