diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 61689a4..08ccbc6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,6 +24,7 @@ jobs:
     uses: ruby/actions/.github/workflows/ruby_versions.yml@master
     with:
       engine: cruby
+      min_version: 3.3
 
   test:
     needs: ruby-versions
@@ -33,7 +34,9 @@ jobs:
       matrix:
         ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
         prism_version:
-          - 1.2.0 # Shipped with Ruby 3.4 as default parser https://www.ruby-lang.org/en/news/2024/12/25/ruby-3-4-0-released/
+          # See https://stdgems.org/prism for which ruby version shipped with which prism version
+          - 0.19.0
+          - 1.2.0
           - 1.8.0
           - head
     env:
@@ -52,22 +55,3 @@ jobs:
       - name: test
         run: bin/rake test
         continue-on-error: ${{ matrix.ruby == 'head' }}
-
-  test-disable-prism:
-    needs: ruby-versions
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v6
-      - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: ${{ matrix.ruby }}
-          bundler-cache: true
-      - name: test
-        run: SYNTAX_SUGGEST_DISABLE_PRISM=1 bin/rake test
-        continue-on-error: ${{ matrix.ruby == 'head' }}
diff --git a/.standard.yml b/.standard.yml
index 2547695..3a33af2 100644
--- a/.standard.yml
+++ b/.standard.yml
@@ -1 +1 @@
-ruby_version: 3.0.0
+ruby_version: 3.3.0
diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc1a0a9..6600c5b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## HEAD (unreleased)
 
+- Changed: Changed: Minimum supported Ruby version is now 3.3. (https://github.com/ruby/syntax_suggest/pull/246)
+
 ## 2.0.3
 
 - Fix: Correctly identify trailing slashes when using Prism > 1.8.0. (https://github.com/ruby/syntax_suggest/pull/243)
diff --git a/lib/syntax_suggest/api.rb b/lib/syntax_suggest/api.rb
index 0f82d83..a86237f 100644
--- a/lib/syntax_suggest/api.rb
+++ b/lib/syntax_suggest/api.rb
@@ -7,26 +7,12 @@
 require "pathname"
 require "timeout"
 
+# Prism is the new parser, replacing Ripper
+require "prism"
 # We need Ripper loaded for `Prism.lex_compat` even if we're using Prism
 # for lexing and parsing
 require "ripper"
 
-# Prism is the new parser, replacing Ripper
-#
-# We need to "dual boot" both for now because syntax_suggest
-# supports older rubies that do not ship with syntax suggest.
-#
-# We also need the ability to control loading of this library
-# so we can test that both modes work correctly in CI.
-if (value = ENV["SYNTAX_SUGGEST_DISABLE_PRISM"])
-  warn "Skipping loading prism due to SYNTAX_SUGGEST_DISABLE_PRISM=#{value}"
-else
-  begin
-    require "prism"
-  rescue LoadError
-  end
-end
-
 module SyntaxSuggest
   # Used to indicate a default value that cannot
   # be confused with another input.
@@ -35,14 +21,6 @@ module SyntaxSuggest
   class Error < StandardError; end
   TIMEOUT_DEFAULT = ENV.fetch("SYNTAX_SUGGEST_TIMEOUT", 1).to_i
 
-  # SyntaxSuggest.use_prism_parser? [Private]
-  #
-  # Tells us if the prism parser is available for use
-  # or if we should fallback to `Ripper`
-  def self.use_prism_parser?
-    defined?(Prism)
-  end
-
   # SyntaxSuggest.handle_error [Public]
   #
   # Takes a `SyntaxError` exception, uses the
@@ -152,20 +130,11 @@ def self.valid_without?(without_lines:, code_lines:)
   # SyntaxSuggest.invalid? [Private]
   #
   # Opposite of `SyntaxSuggest.valid?`
-  if defined?(Prism)
-    def self.invalid?(source)
-      source = source.join if source.is_a?(Array)
-      source = source.to_s
+  def self.invalid?(source)
+    source = source.join if source.is_a?(Array)
+    source = source.to_s
 
-      Prism.parse(source).failure?
-    end
-  else
-    def self.invalid?(source)
-      source = source.join if source.is_a?(Array)
-      source = source.to_s
-
-      Ripper.new(source).tap(&:parse).error?
-    end
+    Prism.parse(source).failure?
   end
 
   # SyntaxSuggest.valid? [Private]
diff --git a/lib/syntax_suggest/explain_syntax.rb b/lib/syntax_suggest/explain_syntax.rb
index 0d80c4d..5d5daa8 100644
--- a/lib/syntax_suggest/explain_syntax.rb
+++ b/lib/syntax_suggest/explain_syntax.rb
@@ -2,18 +2,10 @@
 
 require_relative "left_right_lex_count"
 
-if !SyntaxSuggest.use_prism_parser?
-  require_relative "ripper_errors"
-end
-
 module SyntaxSuggest
   class GetParseErrors
     def self.errors(source)
-      if SyntaxSuggest.use_prism_parser?
-        Prism.parse(source).errors.map(&:message)
-      else
-        RipperErrors.new(source).call.errors
-      end
+      Prism.parse(source).errors.map(&:message)
     end
   end
 
diff --git a/lib/syntax_suggest/lex_all.rb b/lib/syntax_suggest/lex_all.rb
index c16fbb5..c3b4024 100644
--- a/lib/syntax_suggest/lex_all.rb
+++ b/lib/syntax_suggest/lex_all.rb
@@ -1,13 +1,7 @@
 # frozen_string_literal: true
 
 module SyntaxSuggest
-  # Ripper.lex is not guaranteed to lex the entire source document
-  #
-  # This class guarantees the whole document is lex-ed by iteratively
-  # lexing the document where ripper stopped.
-  #
-  # Prism likely doesn't have the same problem. Once ripper support is removed
-  # we can likely reduce the complexity here if not remove the whole concept.
+  # Lexes the whole source and wraps the tokens in `LexValue`.
   #
   # Example usage:
   #
@@ -20,34 +14,14 @@ class LexAll
 
     def initialize(source:, source_lines: nil)
       @lex = self.class.lex(source, 1)
-      lineno = @lex.last[0][0] + 1
-      source_lines ||= source.lines
-      last_lineno = source_lines.length
-
-      until lineno >= last_lineno
-        lines = source_lines[lineno..]
-
-        @lex.concat(
-          self.class.lex(lines.join, lineno + 1)
-        )
-
-        lineno = @lex.last[0].first + 1
-      end
-
       last_lex = nil
       @lex.map! { |elem|
         last_lex = LexValue.new(elem[0].first, elem[1], elem[2], elem[3], last_lex)
       }
     end
 
-    if SyntaxSuggest.use_prism_parser?
-      def self.lex(source, line_number)
-        Prism.lex_compat(source, line: line_number).value.sort_by { |values| values[0] }
-      end
-    else
-      def self.lex(source, line_number)
-        Ripper::Lexer.new(source, "-", line_number).parse.sort_by(&:pos)
-      end
+    def self.lex(source, line_number)
+      Prism.lex_compat(source, line: line_number).value.sort_by { |values| values[0] }
     end
 
     def to_a
diff --git a/lib/syntax_suggest/ripper_errors.rb b/lib/syntax_suggest/ripper_errors.rb
deleted file mode 100644
index 4e2bc90..0000000
--- a/lib/syntax_suggest/ripper_errors.rb
+++ /dev/null
@@ -1,39 +0,0 @@
-# frozen_string_literal: true
-
-module SyntaxSuggest
-  # Capture parse errors from Ripper
-  #
-  # Prism returns the errors with their messages, but Ripper
-  # does not. To get them we must make a custom subclass.
-  #
-  # Example:
-  #
-  #   puts RipperErrors.new(" def foo").call.errors
-  #   # => ["syntax error, unexpected end-of-input, expecting ';' or '\\n'"]
-  class RipperErrors < Ripper
-    attr_reader :errors
-
-    # Comes from ripper, called
-    # on every parse error, msg
-    # is a string
-    def on_parse_error(msg)
-      @errors ||= []
-      @errors << msg
-    end
-
-    alias_method :on_alias_error, :on_parse_error
-    alias_method :on_assign_error, :on_parse_error
-    alias_method :on_class_name_error, :on_parse_error
-    alias_method :on_param_error, :on_parse_error
-    alias_method :compile_error, :on_parse_error
-
-    def call
-      @run_once ||= begin
-        @errors = []
-        parse
-        true
-      end
-      self
-    end
-  end
-end
diff --git a/spec/integration/ruby_command_line_spec.rb b/spec/integration/ruby_command_line_spec.rb
index c1ec4be..02354ce 100644
--- a/spec/integration/ruby_command_line_spec.rb
+++ b/spec/integration/ruby_command_line_spec.rb
@@ -94,8 +94,6 @@ module SyntaxSuggest
     end
 
     it "gem can be tested when executing on Ruby with default gem included" do
-      skip if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("3.2")
-
       out = `#{ruby} -I#{lib_dir} -rsyntax_suggest -e "puts SyntaxError.instance_method(:detailed_message).source_location" 2>&1`
 
       expect($?.success?).to be_truthy
@@ -103,8 +101,6 @@ module SyntaxSuggest
     end
 
     it "annotates a syntax error in Ruby 3.2+ when require is not used" do
-      skip if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("3.2")
-
       Dir.mktmpdir do |dir|
         tmpdir = Pathname(dir)
         script = tmpdir.join("script.rb")
diff --git a/spec/unit/api_spec.rb b/spec/unit/api_spec.rb
index e900b9e..9299a17 100644
--- a/spec/unit/api_spec.rb
+++ b/spec/unit/api_spec.rb
@@ -8,12 +8,6 @@
 
 module SyntaxSuggest
   RSpec.describe "Top level SyntaxSuggest api" do
-    it "doesn't load prism if env var is set" do
-      skip("SYNTAX_SUGGEST_DISABLE_PRISM not set") unless ENV["SYNTAX_SUGGEST_DISABLE_PRISM"]
-
-      expect(SyntaxSuggest.use_prism_parser?).to be_falsey
-    end
-
     it "has a `handle_error` interface" do
       fake_error = Object.new
       def fake_error.message
@@ -69,8 +63,6 @@ def fake_error.message
     end
 
     it "respects highlight API" do
-      skip if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("3.2")
-
       core_ext_file = lib_dir.join("syntax_suggest").join("core_ext.rb")
       require_relative core_ext_file
 
@@ -91,8 +83,6 @@ def detailed_message(**kwargs)
     end
 
     it "can be disabled via falsey kwarg" do
-      skip if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("3.2")
-
       core_ext_file = lib_dir.join("syntax_suggest").join("core_ext.rb")
       require_relative core_ext_file
 
diff --git a/spec/unit/code_line_spec.rb b/spec/unit/code_line_spec.rb
index 5b62cc2..761c460 100644
--- a/spec/unit/code_line_spec.rb
+++ b/spec/unit/code_line_spec.rb
@@ -17,8 +17,6 @@ def to_json(*opts)
     end
 
     it "supports endless method definitions" do
-      skip("Unsupported ruby version") unless Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("3")
-
       line = CodeLine.from_source(<<~EOM).first
         def square(x) = x * x
       EOM
diff --git a/spec/unit/core_ext_spec.rb b/spec/unit/core_ext_spec.rb
index 499c38a..d579cc8 100644
--- a/spec/unit/core_ext_spec.rb
+++ b/spec/unit/core_ext_spec.rb
@@ -3,8 +3,6 @@
 module SyntaxSuggest
   RSpec.describe "Core extension" do
     it "SyntaxError monkepatch ensures there is a newline to the end of the file" do
-      skip if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("3.2")
-
       Dir.mktmpdir do |dir|
         tmpdir = Pathname(dir)
         file = tmpdir.join("file.rb")
diff --git a/syntax_suggest.gemspec b/syntax_suggest.gemspec
index 756a85b..44e458a 100644
--- a/syntax_suggest.gemspec
+++ b/syntax_suggest.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |spec|
   spec.description = 'When you get an "unexpected end" in your syntax this gem helps you find it'
   spec.homepage = "https://github.com/ruby/syntax_suggest.git"
   spec.license = "MIT"
-  spec.required_ruby_version = Gem::Requirement.new(">= 3.0.0")
+  spec.required_ruby_version = Gem::Requirement.new(">= 3.3.0")
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = "https://github.com/ruby/syntax_suggest.git"