diff --git a/lib/capybara/queries/selector_query.rb b/lib/capybara/queries/selector_query.rb
index 2ca6ac9e..d5a1aa91 100644
--- a/lib/capybara/queries/selector_query.rb
+++ b/lib/capybara/queries/selector_query.rb
@@ -18,7 +18,7 @@ module Capybara
         @locator = args.shift
         @filter_block = filter_block
 
-        warn "Unused parameters passed to #{self.class.name} : #{args}" unless args.empty?
+        raise ArgumentError, "Unused parameters passed to #{self.class.name} : #{args}" unless args.empty?
 
         @expression = @selector.call(@locator, @options.merge(enable_aria_label: session_options.enable_aria_label))
 
diff --git a/lib/capybara/spec/session/first_spec.rb b/lib/capybara/spec/session/first_spec.rb
index 3f42d14b..fc8f2d26 100644
--- a/lib/capybara/spec/session/first_spec.rb
+++ b/lib/capybara/spec/session/first_spec.rb
@@ -26,9 +26,10 @@ Capybara::SpecHelper.spec '#first' do
     expect(@session.first(@xpath).value).to eq('John')
   end
 
-  it "should warn when unused parameters are passed" do
-    expect_any_instance_of(Kernel).to receive(:warn).with(/Unused parameters passed.*unused text/)
-    @session.first(:css, 'h1', 'unused text')
+  it "should raise when unused parameters are passed" do
+    expect {
+      @session.first(:css, 'h1', 'unused text')
+    }.to raise_error ArgumentError, /Unused parameters passed.*unused text/
   end
 
   context "with css selectors" do
diff --git a/lib/capybara/spec/session/has_selector_spec.rb b/lib/capybara/spec/session/has_selector_spec.rb
index 3c1e94cc..66f691fd 100644
--- a/lib/capybara/spec/session/has_selector_spec.rb
+++ b/lib/capybara/spec/session/has_selector_spec.rb
@@ -72,9 +72,10 @@ Capybara::SpecHelper.spec '#has_selector?' do
       expect(@session).not_to have_selector("//p//a", text: /Red$/)
     end
 
-    it "should warn when extra parameters passed" do
-      expect_any_instance_of(Kernel).to receive(:warn).with(/extra/)
-      expect(@session).to have_selector(:css, "p a#foo", 'extra')
+    it "should raise when extra parameters passed" do
+      expect {
+        expect(@session).to have_selector(:css, "p a#foo", 'extra')
+      }.to raise_error ArgumentError, /extra/
     end
   end
 
diff --git a/spec/capybara_spec.rb b/spec/capybara_spec.rb
index cd107b5e..bc48a5fb 100644
--- a/spec/capybara_spec.rb
+++ b/spec/capybara_spec.rb
@@ -104,7 +104,7 @@ RSpec.describe Capybara do
       Capybara.default_host = old_default
     end
 
-    it "should warn if not a valid URL" do
+    it "should raise if not a valid URL" do
       expect { Capybara.default_host = "www.example.com" }.to raise_error(ArgumentError, /Capybara\.default_host should be set to a url/)
     end