diff --git a/.rubocop.yml b/.rubocop.yml
index 03af185..6624266 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,4 +1,5 @@
 require:
+  - rubocop-performance
   - rubocop-rake
 
 AllCops:
@@ -41,6 +42,13 @@ Metrics/ModuleLength:
 Metrics/PerceivedComplexity:
   Enabled: false
 
+# TODO: Progressively fix performance offences and remove this setting
+Performance:
+  Enabled: false
+
+Performance/RegexpMatch:
+  Enabled: true
+
 Style/AndOr:
   Enabled: false
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f26d991..e0b0074 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ### Unreleased
 
+* Minor performance improvements
+
 ### Version v1.20.0
 
 * Remove `iconv` conditional require
diff --git a/Gemfile b/Gemfile
index 1ca5eff..4f83719 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,5 +12,6 @@ gem 'maxitest'
 gem 'memory_profiler'
 gem 'rake'
 gem 'rubocop'
+gem 'rubocop-performance'
 gem 'rubocop-rake'
 gem 'webrick'
diff --git a/Gemfile.lock b/Gemfile.lock
index cd6ede7..a8bc568 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -43,6 +43,9 @@ GEM
       unicode-display_width (>= 2.4.0, < 3.0)
     rubocop-ast (1.31.2)
       parser (>= 3.3.0.4)
+    rubocop-performance (1.23.0)
+      rubocop (>= 1.48.1, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
     rubocop-rake (0.6.0)
       rubocop (~> 1.0)
     ruby-progressbar (1.13.0)
@@ -61,6 +64,7 @@ DEPENDENCIES
   memory_profiler
   rake
   rubocop
+  rubocop-performance
   rubocop-rake
   webrick
 
diff --git a/lib/css_parser.rb b/lib/css_parser.rb
index 2fbbd20..774245d 100644
--- a/lib/css_parser.rb
+++ b/lib/css_parser.rb
@@ -138,7 +138,7 @@ def self.convert_uris(css, base_uri)
     css.gsub(URI_RX) do
       uri = Regexp.last_match(1).to_s.gsub(/["']+/, '')
       # Don't process URLs that are already absolute
-      unless uri.match(%r{^[a-z]+://}i)
+      unless uri.match?(%r{^[a-z]+://}i)
         begin
           uri = base_uri.join(uri)
         rescue
diff --git a/lib/css_parser/parser.rb b/lib/css_parser/parser.rb
index e199e3b..f027ce8 100644
--- a/lib/css_parser/parser.rb
+++ b/lib/css_parser/parser.rb
@@ -416,7 +416,7 @@ def parse_block_into_rule_sets!(block, options = {}) # :nodoc:
             # restart our search for selectors and declarations
             rule_start = nil if options[:capture_offsets]
           end
-        elsif token =~ /@media/i
+        elsif /@media/i.match?(token)
           # found '@media', reset current media_types
           in_at_media_rule = true
           current_media_queries = []
@@ -718,7 +718,7 @@ def css_node_to_h(hash, key, val)
       nodes = {}
       lines.each do |line|
         parts = line.split(':', 2)
-        if parts[1] =~ /:/
+        if /:/.match?(parts[1])
           nodes[parts[0]] = css_node_to_h(hash, parts[0], parts[1])
         else
           nodes[parts[0].to_s.strip] = parts[1].to_s.strip
diff --git a/lib/css_parser/rule_set.rb b/lib/css_parser/rule_set.rb
index 58ce513..d1bd4a8 100644
--- a/lib/css_parser/rule_set.rb
+++ b/lib/css_parser/rule_set.rb
@@ -455,17 +455,17 @@ def expand_font_shorthand! # :nodoc:
           else
             font_props['font-family'] = m
           end
-        elsif m =~ /normal|inherit/i
+        elsif /normal|inherit/i.match?(m)
           ['font-style', 'font-weight', 'font-variant'].each do |font_prop|
             font_props[font_prop] ||= m
           end
-        elsif m =~ /italic|oblique/i
+        elsif /italic|oblique/i.match?(m)
           font_props['font-style'] = m
-        elsif m =~ /small-caps/i
+        elsif /small-caps/i.match?(m)
           font_props['font-variant'] = m
-        elsif m =~ /[1-9]00$|bold|bolder|lighter/i
+        elsif /[1-9]00$|bold|bolder|lighter/i.match?(m)
           font_props['font-weight'] = m
-        elsif m =~ CssParser::FONT_UNITS_RX
+        elsif CssParser::FONT_UNITS_RX.match?(m)
           if m.include?('/')
             font_props['font-size'], font_props['line-height'] = m.split('/', 2)
           else
@@ -488,7 +488,7 @@ def expand_list_style_shorthand! # :nodoc:
       value = declaration.value.dup
 
       replacement =
-        if value =~ CssParser::RE_INHERIT
+        if CssParser::RE_INHERIT.match?(value)
           LIST_STYLE_PROPERTIES.to_h { |key| [key, 'inherit'] }
         else
           {
@@ -559,7 +559,7 @@ def create_border_shorthand! # :nodoc:
         next if declaration.important
         # can't merge if any value contains a space (i.e. has multiple values)
         # we temporarily remove any spaces after commas for the check (inside rgba, etc...)
-        next if declaration.value.gsub(/,\s/, ',').strip =~ /\s/
+        next if /\s/.match?(declaration.value.gsub(/,\s/, ',').strip)
 
         declaration.value
       end.compact