diff --git a/src/wp-includes/class-wp-term.php b/src/wp-includes/class-wp-term.php
index 0cefa3097b393..8d0f243f01e98 100644
--- a/src/wp-includes/class-wp-term.php
+++ b/src/wp-includes/class-wp-term.php
@@ -124,7 +124,7 @@ public static function get_instance( $term_id, $taxonomy = null ) {
 		$_term = wp_cache_get( $term_id, 'terms' );
 
 		// If there isn't a cached version, hit the database.
-		if ( ! $_term || ( $taxonomy && $taxonomy !== $_term->taxonomy ) ) {
+		if ( ! is_object( $_term ) || ! isset( $_term->taxonomy ) || ( $taxonomy && $taxonomy !== $_term->taxonomy ) ) {
 			// Any term found in the cache is not a match, so don't use it.
 			$_term = false;
 
diff --git a/tests/phpunit/tests/term/wpTerm.php b/tests/phpunit/tests/term/wpTerm.php
index e640cf8120732..d67f0bd086345 100644
--- a/tests/phpunit/tests/term/wpTerm.php
+++ b/tests/phpunit/tests/term/wpTerm.php
@@ -89,4 +89,36 @@ public function test_get_instance_should_respect_taxonomy_when_term_id_is_found_
 		$found = WP_Term::get_instance( self::$term_id, 'wptests_tax2' );
 		$this->assertFalse( $found );
 	}
+
+	/**
+	 * @ticket 65915
+	 *
+	 * @dataProvider data_get_instance_should_ignore_unusable_cached_values
+	 *
+	 * @param mixed $cached_value A cached value that is not a usable term object.
+	 */
+	public function test_get_instance_should_ignore_unusable_cached_values( $cached_value ) {
+		wp_cache_set( self::$term_id, $cached_value, 'terms' );
+
+		$found = WP_Term::get_instance( self::$term_id );
+
+		$this->assertInstanceOf( WP_Term::class, $found );
+		$this->assertSame( self::$term_id, $found->term_id );
+		$this->assertSame( 'wptests_tax', $found->taxonomy );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array<non-falsy-string, array{ 0: mixed }>
+	 */
+	public function data_get_instance_should_ignore_unusable_cached_values(): array {
+		return array(
+			'an array'                       => array( array( 'term_id' => 12345 ) ),
+			'an integer'                     => array( 12345 ),
+			'a string'                       => array( 'a term' ),
+			'an object with no taxonomy'     => array( (object) array( 'term_id' => 12345 ) ),
+			'an object with a null taxonomy' => array( (object) array( 'taxonomy' => null ) ),
+		);
+	}
 }