diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 00dfdb9..d0c97ec 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12"]
 
     steps:
       - name: Checkout
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2a6d508..db4a746 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Removed
+- **Dropped support for Python 3.9** (end-of-life since October 2025).
+  Minimum supported version is now Python 3.10. This unblocks dev-tool
+  upgrades (pytest 9, build 1.5+) that no longer support 3.9. Closes #44.
+
 ### Fixed
 - Augmented assignments no longer produce invalid-variable-name linter errors.
 
diff --git a/README.md b/README.md
index 16d69c3..7c9e827 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ python_maithili examples/hello.dmai
 # or, without installing the console script:
 python -m maithili_dsl examples/hello.dmai
 ```
-✅ Works on Mac, Windows, and Linux, on Python 3.9 – 3.12.
+✅ Works on Mac, Windows, and Linux, on Python 3.10 – 3.12.
 
 ---
 
diff --git a/pyproject.toml b/pyproject.toml
index 77745a3..7639468 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,10 +11,9 @@ license = { file = "LICENSE" }
 authors = [
     { name = "Bishwas Jha", email = "jha.bishwas@gmail.com" },
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 classifiers = [
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
diff --git a/setup.py b/setup.py
index f6ea8c9..077aea9 100644
--- a/setup.py
+++ b/setup.py
@@ -35,12 +35,11 @@ def _read_version() -> str:
     },
     classifiers=[
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3.11',
         'Programming Language :: Python :: 3.12',
         'License :: OSI Approved :: MIT License',
         'Operating System :: OS Independent',
     ],
-    python_requires='>=3.9',
+    python_requires='>=3.10',
 )