diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index 12dc1868a3..9551a61c65 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -158,6 +158,11 @@ function wptexturize($text) {
 		$dynamic_replacements = array_values( $dynamic );
 	}
 
+	// If there's nothing to do, just stop.
+	if ( empty( $text ) ) {
+		return $text;
+	}
+
 	// Transform into regexp sub-expression used in _wptexturize_pushpop_element
 	// Must do this every time in case plugins use these filters in a context sensitive manner
 	/**
@@ -180,25 +185,50 @@ function wptexturize($text) {
 	$no_texturize_tags_stack = array();
 	$no_texturize_shortcodes_stack = array();
 
-	$textarr = preg_split('/(<.*>|\[.*\])/Us', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
+	// Look for shortcodes and HTML elements.
+
+	$regex =  '/('			// Capture the entire match.
+		.	'<'		// Find start of element.
+		.	'(?(?=!--)'	// Is this a comment?
+		.		'.+?--\s*>'	// Find end of comment
+		.	'|'
+		.		'.+?>'		// Find end of element
+		.	')'
+		. '|'
+		.	'\['		// Find start of shortcode.
+		.	'\[?'		// Shortcodes may begin with [[
+		.	'[^\[\]<>]+'	// Shortcodes do not contain other shortcodes or HTML elements.
+		.	'\]'		// Find end of shortcode.
+		.	'\]?'		// Shortcodes may end with ]]
+		. ')/s';
+
+	$textarr = preg_split( $regex, $text, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY );
 
 	foreach ( $textarr as &$curl ) {
-		if ( empty( $curl ) ) {
-			continue;
-		}
-
-		// Only call _wptexturize_pushpop_element if first char is correct tag opening
+		// Only call _wptexturize_pushpop_element if $curl is a delimeter.
 		$first = $curl[0];
-		if ( '<' === $first ) {
-			_wptexturize_pushpop_element($curl, $no_texturize_tags_stack, $no_texturize_tags, '<', '>');
-		} elseif ( '[' === $first ) {
-			_wptexturize_pushpop_element($curl, $no_texturize_shortcodes_stack, $no_texturize_shortcodes, '[', ']');
+		if ( '<' === $first && '>' === substr( $curl, -1 ) ) {
+			// This is an HTML delimeter.
+
+			if ( '<!--' !== substr( $curl, 0, 4 ) ) {
+				_wptexturize_pushpop_element( $curl, $no_texturize_tags_stack, $no_texturize_tags, '<', '>' );
+			}
+
+		} elseif ( '[' === $first && 1 === preg_match( '/^\[[^\[\]<>]+\]$/', $curl ) ) {
+			// This is a shortcode delimeter.
+
+			_wptexturize_pushpop_element( $curl, $no_texturize_shortcodes_stack, $no_texturize_shortcodes, '[', ']' );
+
+		} elseif ( '[' === $first && 1 === preg_match( '/^\[\[?[^\[\]<>]+\]\]?$/', $curl ) ) {
+			// This is an escaped shortcode delimeter.
+
+			// Do not texturize.
+			// Do not push to the shortcodes stack.
+
 		} elseif ( empty($no_texturize_shortcodes_stack) && empty($no_texturize_tags_stack) ) {
+			// This is neither a delimeter, nor is this content inside of no_texturize pairs.  Do texturize.
 
-			// This is not a tag, nor is the texturization disabled static strings
 			$curl = str_replace($static_characters, $static_replacements, $curl);
-
-			// regular expressions
 			$curl = preg_replace($dynamic_characters, $dynamic_replacements, $curl);
 
 			// 9x9 (times), but never 0x9999
diff --git a/tests/phpunit/tests/formatting/WPTexturize.php b/tests/phpunit/tests/formatting/WPTexturize.php
index 21918d1966..63647334c9 100644
--- a/tests/phpunit/tests/formatting/WPTexturize.php
+++ b/tests/phpunit/tests/formatting/WPTexturize.php
@@ -1128,4 +1128,155 @@ class Tests_Formatting_WPTexturize extends WP_UnitTestCase {
 			),
 		);
 	}
+
+	/**
+	 * Test HTML and shortcode avoidance.
+	 *
+	 * @ticket 12690
+	 * @dataProvider data_tag_avoidance
+	 */
+	function test_tag_avoidance( $input, $output ) {
+		return $this->assertEquals( $output, wptexturize( $input ) );
+	}
+
+	function data_tag_avoidance() {
+		return array(
+			array(
+				'[ photos by <a href="http://example.com/?a[]=1&a[]=2"> this guy </a> ]',
+				'[ photos by <a href="http://example.com/?a[]=1&#038;a[]=2"> this guy </a> ]',
+			),
+			array(
+				'[gallery ...]',
+				'[gallery ...]',
+			),
+			array(
+				'[[gallery ...]', // This tag is still valid.
+				'[[gallery ...]',
+			),
+			array(
+				'[gallery ...]]', // This tag is also valid.
+				'[gallery ...]]',
+			),
+			array(
+				'[/...]', // This would actually be ignored by the shortcode system.  The decision to not texturize it is intentional, if not correct.
+				'[/...]',
+			),
+			array(
+				'[...]...[/...]', // These are potentially usable shortcodes.
+				'[...]&#8230;[/...]',
+			),
+			array(
+				'[[...]]...[[/...]]', // Shortcode parsing will ignore the inner ]...[ part and treat this as a single escaped shortcode.
+				'[[...]]&#8230;[[/...]]',
+			),
+			array(
+				'[[[...]]]...[[[/...]]]', // Again, shortcode parsing matches, but only the [[...] and [/...]] parts.
+				'[[[...]]]&#8230;[[[/...]]]',
+			),
+			array(
+				'[[code]...[/code]...', // These are potentially usable shortcodes.  Unfortunately, the meaning of [[/code] is ambiguous unless we run the entire shortcode regexp.
+				'[[code]&#8230;[/code]...', // Same behavior as 3.9 due to buggy logic in _wptexturize_pushpop_element().  See ticket #28483.
+			),
+			array(
+				'[code]...[/code]]...', // These are potentially usable shortcodes.  Unfortunately, the meaning of [/code]] is ambiguous unless we run the entire shortcode regexp.
+				'[code]...[/code]]...', // This test would not pass in 3.9 because the extra brace was always ignored by texturize.
+			),
+			array(
+				'[gal>ery ...]',
+				'[gal>ery &#8230;]',
+			),
+			array(
+				'[gallery ...',
+				'[gallery &#8230;',
+			),
+			array(
+				'[gallery <br ... /> ...]',
+				'[gallery <br ... /> &#8230;]',
+			),
+			array(
+				'<br [gallery ...] ... />',
+				'<br [gallery ...] ... />',
+			),
+			array(
+				'<br [gallery ...] ... /',
+				'<br [gallery ...] &#8230; /',
+			),
+			array(
+				'<br ... />',
+				'<br ... />',
+			),
+			array(
+				'<br ... />...<br ... />',
+				'<br ... />&#8230;<br ... />',
+			),
+			array(
+				'[gallery ...]...[gallery ...]',
+				'[gallery ...]&#8230;[gallery ...]',
+			),
+			array(
+				'[[gallery ...]]',
+				'[[gallery ...]]',
+			),
+			array(
+				'[[gallery ...]',
+				'[[gallery ...]',
+			),
+			array(
+				'[gallery ...]]',
+				'[gallery ...]]',
+			),
+			array(
+				'[/gallery ...]]',
+				'[/gallery ...]]',
+			),
+			array(
+				'[[gallery <br ... /> ...]]',
+				'[[gallery <br ... /> &#8230;]]',
+			),
+			array(
+				'<br [[gallery ...]] ... />',
+				'<br [[gallery ...]] ... />',
+			),
+			array(
+				'<br [[gallery ...]] ... /',
+				'<br [[gallery ...]] &#8230; /',
+			),
+			array(
+				'[[gallery ...]]...[[gallery ...]]',
+				'[[gallery ...]]&#8230;[[gallery ...]]',
+			),
+			array(
+				'[[gallery ...]...[/gallery]]',
+				'[[gallery ...]&#8230;[/gallery]]',
+			),
+			array(
+				'<!-- ... -->',
+				'<!-- ... -->',
+			),
+			array(
+				'<!--...-->',
+				'<!--...-->',
+			),
+			array(
+				'<!-- ... -- >',
+				'<!-- ... -- >',
+			),
+			array(
+				'<!-- <br /> [gallery] ... -->',
+				'<!-- <br /> [gallery] ... -->',
+			),
+			array(
+				'...<!-- ... -->...',
+				'&#8230;<!-- ... -->&#8230;',
+			),
+			array(
+				'[gallery ...]...<!-- ... -->...<br ... />',
+				'[gallery ...]&#8230;<!-- ... -->&#8230;<br ... />',
+			),
+			array(
+				'<ul><li>Hello.</li><!--<li>Goodbye.</li>--></ul>',
+				'<ul><li>Hello.</li><!--<li>Goodbye.</li>--></ul>',
+			),
+		);
+	}
 }