diff --git a/src/ApacheModRewriteGenerator.php b/src/ApacheModRewriteGenerator.php
index 45f3f1b..dc2ebe4 100644
--- a/src/ApacheModRewriteGenerator.php
+++ b/src/ApacheModRewriteGenerator.php
@@ -3,6 +3,7 @@
 namespace donatj\RewriteGenerator;
 
 use donatj\RewriteGenerator\Exceptions\AmbiguousRelativeHostException;
+use donatj\RewriteGenerator\Exceptions\MismatchedSchemeException;
 use donatj\RewriteGenerator\Exceptions\UnhandledUrlException;
 use InvalidArgumentException;
 
@@ -29,7 +30,8 @@ public function generateRewrite( string $from, string $to, int $type ) : string
 			);
 		}
 
-		$toScheme = $parsedTo['scheme'] ?? '';
+		$fromScheme = $parsedFrom['scheme'] ?? '';
+		$toScheme   = $parsedTo['scheme'] ?? '';
 
 		$fromHost = $parsedFrom['host'] ?? '';
 		$toHost   = $parsedTo['host'] ?? '';
@@ -47,6 +49,11 @@ public function generateRewrite( string $from, string $to, int $type ) : string
 				'Unclear relative host. When the "FROM" URI specifies a HOST the "TO" MUST specify a HOST as well.'
 			);
 		}
+
+		if( $fromScheme && $toScheme && $toHost && $fromScheme !== $toScheme && $fromHost === $toHost ) {
+			throw new MismatchedSchemeException('Scheme specified on "FROM" of "' . $fromScheme . '" and "TO" of "' . $toScheme . '" do not match.');
+		}
+
 		if( $toHost && $fromHost !== $toHost ) {
 			$output .= 'RewriteCond %{HTTP_HOST} ^' . preg_quote($fromHost, ' ') . '$';
 			$output .= "\n";
diff --git a/src/Exceptions/MismatchedSchemeException.php b/src/Exceptions/MismatchedSchemeException.php
new file mode 100644
index 0000000..f337e38
--- /dev/null
+++ b/src/Exceptions/MismatchedSchemeException.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace donatj\RewriteGenerator\Exceptions;
+
+class MismatchedSchemeException extends GenerationException {
+
+}
diff --git a/tests/tests/ApacheIntegrationTest.php b/tests/tests/ApacheIntegrationTest.php
index d24fa6e..8048a8d 100644
--- a/tests/tests/ApacheIntegrationTest.php
+++ b/tests/tests/ApacheIntegrationTest.php
@@ -131,6 +131,27 @@ public function exampleProvider() : Generator {
 			,
 		];
 
+		// Assure Redirects across Schemes do not error.
+		yield [
+			<<<'TAG'
+http://foo.bar/baz	https://baz.qux/quux
+TAG
+			,
+			<<<'TAG'
+# 301 --- http://foo.bar/baz => https://baz.qux/quux
+RewriteCond %{HTTP_HOST} ^foo\.bar$
+RewriteRule ^baz$ https://baz.qux/quux? [L,R=301]
+
+TAG
+			,
+			<<<'TAG'
+# Rewrite --- http://foo.bar/baz => https://baz.qux/quux
+RewriteCond %{HTTP_HOST} ^foo\.bar$
+RewriteRule ^baz$ https://baz.qux/quux?&%{QUERY_STRING}
+
+TAG
+			,
+		];
 	}
 
 	/**
@@ -204,6 +225,22 @@ public function failureProvider() : Generator {
 			, 3,
 		];
 
+		// Ensure an error is thrown if the HOST is the same but the SCHEME varies
+		yield [
+			<<<'TAG'
+http://foo.bar/baz	https://foo.bar/baz
+TAG
+			,
+			<<<'TAG'
+# WARNING: Input contained 1 error(s)
+
+# 301 --- http://foo.bar/baz => https://foo.bar/baz
+# ERROR: Scheme specified on "FROM" of "http" and "TO" of "https" do not match.: http://foo.bar/baz	https://foo.bar/baz
+
+TAG
+			, 1,
+		];
+
 		yield [
 			<<<'TAG'
 foo.html#funk	bar.html