diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6d0fd56..1063de0 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -26,6 +26,7 @@ jobs:
           - '3.0'
           - '2.7'
           - '2.6'
+          - '2.5'
         libre2:
           - version: "20150501"
             soname: 0
@@ -74,8 +75,10 @@ jobs:
       fail-fast: false
       matrix:
         runs-on: ["ubuntu-latest", "macos-latest"]
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
         include:
+          - ruby: "2.5"
+            runs-on: "windows-2019"
           - ruby: "2.6"
             runs-on: "windows-2019"
           - ruby: "2.7"
@@ -122,7 +125,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -140,7 +143,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v3
@@ -158,7 +161,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0"]
+        ruby: ["2.5", "2.6", "2.7", "3.0"]
     runs-on: windows-latest
     steps:
       - uses: actions/checkout@v3
@@ -226,7 +229,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -239,15 +242,15 @@ jobs:
       - run: |
           docker run --rm -v "$(pwd):/re2" -w /re2 \
             --platform=linux/arm64/v8 \
-            ruby:${{matrix.ruby}} \
-            ./scripts/test-gem-install ./gems
+            ruby:${{matrix.ruby}}-alpine \
+            ./scripts/test-gem-install-sh ./gems
 
   test-precompiled-arm-linux:
     needs: ["build-precompiled-gems"]
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -260,8 +263,8 @@ jobs:
       - run: |
           docker run --rm -v "$(pwd):/re2" -w /re2 \
             --platform=linux/arm/v7 \
-            ruby:${{matrix.ruby}} \
-            ./scripts/test-gem-install ./gems
+            ruby:${{matrix.ruby}}-alpine \
+            ./scripts/test-gem-install-sh ./gems
 
   test-precompiled-x64-mingw-ucrt:
     needs: ["build-precompiled-gems"]
@@ -287,7 +290,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0"]
+        ruby: ["2.5", "2.6", "2.7", "3.0"]
     runs-on: windows-2019
     steps:
       - uses: actions/checkout@v3
@@ -306,7 +309,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -327,7 +330,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -345,7 +348,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v3
@@ -363,7 +366,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2"]
     runs-on: ubuntu-latest
     container:
       image: "ruby:${{matrix.ruby}}-alpine"
diff --git a/README.md b/README.md
index fe318fd..b4fffea 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ A Ruby binding to [re2][], an "efficient, principled regular expression
 library".
 
 **Current version:** 2.0.0.beta1  
-**Supported Ruby versions:** 2.7, 3.0, 3.1, 3.2  
+**Supported Ruby versions:** 2.5, 2.6, 2.7, 3.0, 3.1, 3.2  
 **Bundled re2 version:** libre2.11 (2023-09-01)  
 **Supported re2 versions:** libre2.0 (< 2020-03-02), libre2.1 (2020-03-02), libre2.6 (2020-03-03), libre2.7 (2020-05-01), libre2.8 (2020-07-06), libre2.9 (2020-11-01), libre2.10 (2022-12-01), libre2.11 (2023-07-01)
 
@@ -16,7 +16,7 @@ The gem comes bundled with a version of [re2][] and will compile itself (and
 any dependencies) on install. As compilation can take a while, precompiled
 native gems are available for Linux, Windows and macOS.
 
-In v2.0 and later, precompiled native gems are available for Ruby 2.7 to 3.2
+In v2.0 and later, precompiled native gems are available for Ruby 2.5 to 3.2
 on these platforms:
 
 - `aarch64-linux` (requires: glibc >= 2.29)
diff --git a/Rakefile b/Rakefile
index 4712797..e1cefd8 100644
--- a/Rakefile
+++ b/Rakefile
@@ -33,7 +33,7 @@ Gem::PackageTask.new(RE2_GEM_SPEC) do |p|
   p.need_tar = false
 end
 
-CROSS_RUBY_VERSIONS = %w[3.2.0 3.1.0 3.0.0 2.7.0 2.6.0].join(':')
+CROSS_RUBY_VERSIONS = %w[3.2.0 3.1.0 3.0.0 2.7.0 2.6.0 2.5.0].join(':')
 CROSS_RUBY_PLATFORMS = %w[
   aarch64-linux
   arm-linux
diff --git a/re2.gemspec b/re2.gemspec
index dd2d358..573920b 100644
--- a/re2.gemspec
+++ b/re2.gemspec
@@ -9,7 +9,7 @@ Gem::Specification.new do |s|
   s.homepage = "https://github.com/mudge/re2"
   s.extensions = ["ext/re2/extconf.rb"]
   s.license = "BSD-3-Clause"
-  s.required_ruby_version = ">= 2.6.0"
+  s.required_ruby_version = ">= 2.5.0"
   s.files = [
     ".rspec",
     "dependencies.yml",
diff --git a/scripts/test-gem-install-sh b/scripts/test-gem-install-sh
new file mode 100755
index 0000000..dcfc164
--- /dev/null
+++ b/scripts/test-gem-install-sh
@@ -0,0 +1,9 @@
+#! /usr/bin/env sh
+#
+#  run as part of CI
+#
+if [ -f /etc/alpine-release ]; then
+    apk add bash gcompat
+fi
+
+./scripts/test-gem-install $@