diff --git a/driver.go b/driver.go
index 105a2af..050aeef 100644
--- a/driver.go
+++ b/driver.go
@@ -44,7 +44,7 @@ func New() (db *sql.DB, mock *Sqlmock, err error) {
 	dsn := fmt.Sprintf("sqlmock_db_%d", pool.counter)
 	pool.counter++
 
-	mock = &Sqlmock{dsn: dsn, drv: pool}
+	mock = &Sqlmock{dsn: dsn, drv: pool, MatchExpectationsInOrder: true}
 	pool.conns[dsn] = mock
 	pool.Unlock()
 
diff --git a/expectations.go b/expectations.go
index 909c499..e4f2a2c 100644
--- a/expectations.go
+++ b/expectations.go
@@ -4,6 +4,7 @@ import (
 	"database/sql/driver"
 	"reflect"
 	"regexp"
+	"sync"
 )
 
 // Argument interface allows to match
@@ -16,11 +17,14 @@ type Argument interface {
 // an expectation interface
 type expectation interface {
 	fulfilled() bool
+	Lock()
+	Unlock()
 }
 
 // common expectation struct
 // satisfies the expectation interface
 type commonExpectation struct {
+	sync.Mutex
 	triggered bool
 	err       error
 }
@@ -184,6 +188,19 @@ type queryBasedExpectation struct {
 	args     []driver.Value
 }
 
+func (e *queryBasedExpectation) attemptMatch(sql string, args []driver.Value) (ret bool) {
+	if !e.queryMatches(sql) {
+		return
+	}
+
+	defer recover() // ignore panic since we attempt a match
+
+	if e.argsMatches(args) {
+		return true
+	}
+	return
+}
+
 func (e *queryBasedExpectation) queryMatches(sql string) bool {
 	return e.sqlRegex.MatchString(sql)
 }
diff --git a/sqlmock.go b/sqlmock.go
index 4a44673..8490590 100644
--- a/sqlmock.go
+++ b/sqlmock.go
@@ -22,6 +22,15 @@ import (
 // create expectations for any kind of database action
 // in order to mock and test real database behavior.
 type Sqlmock struct {
+
+	// MatchExpectationsInOrder gives an option whether to match all
+	// expectations in the order they were set or not.
+	//
+	// By default it is set to - true. But if you use goroutines
+	// to parallelize your query executation, that option may
+	// be handy.
+	MatchExpectationsInOrder bool
+
 	dsn    string
 	opened int
 	drv    *mockDriver
@@ -29,15 +38,6 @@ type Sqlmock struct {
 	expected []expectation
 }
 
-func (c *Sqlmock) next() (e expectation) {
-	for _, e = range c.expected {
-		if !e.fulfilled() {
-			return
-		}
-	}
-	return nil // all expectations were fulfilled
-}
-
 // ExpectClose queues an expectation for this database
 // action to be triggered. the *ExpectedClose allows
 // to mock database response
@@ -59,17 +59,32 @@ func (c *Sqlmock) Close() error {
 	if c.opened == 0 {
 		delete(c.drv.conns, c.dsn)
 	}
-	e := c.next()
-	if e == nil {
+
+	var expected *ExpectedClose
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if expected, ok = next.(*ExpectedClose); ok {
+			break
+		}
+
+		next.Unlock()
+		if c.MatchExpectationsInOrder {
+			return fmt.Errorf("call to database Close, was not expected, next expectation is %T as %+v", next, next)
+		}
+	}
+	if expected == nil {
 		return fmt.Errorf("all expectations were already fulfilled, call to database Close was not expected")
 	}
 
-	t, ok := e.(*ExpectedClose)
-	if !ok {
-		return fmt.Errorf("call to database Close, was not expected, next expectation is %T as %+v", e, e)
-	}
-	t.triggered = true
-	return t.err
+	expected.triggered = true
+	expected.Unlock()
+	return expected.err
 }
 
 // ExpectationsWereMet checks whether all queued expectations
@@ -85,17 +100,31 @@ func (c *Sqlmock) ExpectationsWereMet() error {
 
 // Begin meets http://golang.org/pkg/database/sql/driver/#Conn interface
 func (c *Sqlmock) Begin() (driver.Tx, error) {
-	e := c.next()
-	if e == nil {
+	var expected *ExpectedBegin
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if expected, ok = next.(*ExpectedBegin); ok {
+			break
+		}
+
+		next.Unlock()
+		if c.MatchExpectationsInOrder {
+			return nil, fmt.Errorf("call to begin transaction, was not expected, next expectation is %T as %+v", next, next)
+		}
+	}
+	if expected == nil {
 		return nil, fmt.Errorf("all expectations were already fulfilled, call to begin transaction was not expected")
 	}
 
-	t, ok := e.(*ExpectedBegin)
-	if !ok {
-		return nil, fmt.Errorf("call to begin transaction, was not expected, next expectation is %T as %+v", e, e)
-	}
-	t.triggered = true
-	return c, t.err
+	expected.triggered = true
+	expected.Unlock()
+	return c, expected.err
 }
 
 // ExpectBegin expects *sql.DB.Begin to be called.
@@ -108,37 +137,65 @@ func (c *Sqlmock) ExpectBegin() *ExpectedBegin {
 
 // Exec meets http://golang.org/pkg/database/sql/driver/#Execer
 func (c *Sqlmock) Exec(query string, args []driver.Value) (res driver.Result, err error) {
-	e := c.next()
 	query = stripQuery(query)
-	if e == nil {
+	var expected *ExpectedExec
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if c.MatchExpectationsInOrder {
+			if expected, ok = next.(*ExpectedExec); ok {
+				break
+			}
+			next.Unlock()
+			return nil, fmt.Errorf("call to exec query '%s' with args %+v, was not expected, next expectation is %T as %+v", query, args, next, next)
+		}
+		if exec, ok := next.(*ExpectedExec); ok {
+			if exec.attemptMatch(query, args) {
+				expected = exec
+				break
+			}
+		}
+		next.Unlock()
+	}
+	if expected == nil {
 		return nil, fmt.Errorf("all expectations were already fulfilled, call to exec '%s' query with args %+v was not expected", query, args)
 	}
 
-	t, ok := e.(*ExpectedExec)
-	if !ok {
-		return nil, fmt.Errorf("call to exec query '%s' with args %+v, was not expected, next expectation is %T as %+v", query, args, e, e)
+	defer expected.Unlock()
+	expected.triggered = true
+	// converts panic to error in case of reflect value type mismatch
+	defer func(errp *error, exp *ExpectedExec, q string, a []driver.Value) {
+		if e := recover(); e != nil {
+			if se, ok := e.(*reflect.ValueError); ok { // catch reflect error, failed type conversion
+				msg := "exec query \"%s\", args \"%+v\" failed to match expected arguments \"%+v\", reason %s"
+				*errp = fmt.Errorf(msg, q, a, exp.args, se)
+			} else {
+				panic(e) // overwise if unknown error panic
+			}
+		}
+	}(&err, expected, query, args)
+
+	if !expected.queryMatches(query) {
+		return nil, fmt.Errorf("exec query '%s', does not match regex '%s'", query, expected.sqlRegex.String())
 	}
 
-	t.triggered = true
-	if t.err != nil {
-		return nil, t.err // mocked to return error
+	if !expected.argsMatches(args) {
+		return nil, fmt.Errorf("exec query '%s', args %+v does not match expected %+v", query, args, expected.args)
 	}
 
-	if t.result == nil {
-		return nil, fmt.Errorf("exec query '%s' with args %+v, must return a database/sql/driver.result, but it was not set for expectation %T as %+v", query, args, t, t)
+	if expected.err != nil {
+		return nil, expected.err // mocked to return error
 	}
 
-	defer argMatcherErrorHandler(&err) // converts panic to error in case of reflect value type mismatch
-
-	if !t.queryMatches(query) {
-		return nil, fmt.Errorf("exec query '%s', does not match regex '%s'", query, t.sqlRegex.String())
+	if expected.result == nil {
+		return nil, fmt.Errorf("exec query '%s' with args %+v, must return a database/sql/driver.result, but it was not set for expectation %T as %+v", query, args, expected, expected)
 	}
-
-	if !t.argsMatches(args) {
-		return nil, fmt.Errorf("exec query '%s', args %+v does not match expected %+v", query, args, t.args)
-	}
-
-	return t.result, err
+	return expected.result, err
 }
 
 // ExpectExec expects Exec() to be called with sql query
@@ -153,23 +210,33 @@ func (c *Sqlmock) ExpectExec(sqlRegexStr string) *ExpectedExec {
 
 // Prepare meets http://golang.org/pkg/database/sql/driver/#Conn interface
 func (c *Sqlmock) Prepare(query string) (driver.Stmt, error) {
-	e := c.next()
+	var expected *ExpectedPrepare
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if expected, ok = next.(*ExpectedPrepare); ok {
+			break
+		}
+
+		next.Unlock()
+		if c.MatchExpectationsInOrder {
+			return nil, fmt.Errorf("call to Prepare stetement with query '%s', was not expected, next expectation is %T as %+v", query, next, next)
+		}
+	}
 
 	query = stripQuery(query)
-	if e == nil {
+	if expected == nil {
 		return nil, fmt.Errorf("all expectations were already fulfilled, call to Prepare '%s' query was not expected", query)
 	}
-	t, ok := e.(*ExpectedPrepare)
-	if !ok {
-		return nil, fmt.Errorf("call to Prepare stetement with query '%s', was not expected, next expectation is %T as %+v", query, e, e)
-	}
 
-	t.triggered = true
-	if t.err != nil {
-		return nil, t.err // mocked to return error
-	}
-
-	return &statement{c, query, t.closeErr}, nil
+	expected.triggered = true
+	expected.Unlock()
+	return &statement{c, query, expected.closeErr}, expected.err
 }
 
 // ExpectPrepare expects Prepare() to be called with sql query
@@ -185,37 +252,66 @@ func (c *Sqlmock) ExpectPrepare(sqlRegexStr string) *ExpectedPrepare {
 
 // Query meets http://golang.org/pkg/database/sql/driver/#Queryer
 func (c *Sqlmock) Query(query string, args []driver.Value) (rw driver.Rows, err error) {
-	e := c.next()
 	query = stripQuery(query)
-	if e == nil {
+	var expected *ExpectedQuery
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if c.MatchExpectationsInOrder {
+			if expected, ok = next.(*ExpectedQuery); ok {
+				break
+			}
+			next.Unlock()
+			return nil, fmt.Errorf("call to query '%s' with args %+v, was not expected, next expectation is %T as %+v", query, args, next, next)
+		}
+		if qr, ok := next.(*ExpectedQuery); ok {
+			if qr.attemptMatch(query, args) {
+				expected = qr
+				break
+			}
+		}
+		next.Unlock()
+	}
+	if expected == nil {
 		return nil, fmt.Errorf("all expectations were already fulfilled, call to query '%s' with args %+v was not expected", query, args)
 	}
 
-	t, ok := e.(*ExpectedQuery)
-	if !ok {
-		return nil, fmt.Errorf("call to query '%s' with args %+v, was not expected, next expectation is %T as %+v", query, args, e, e)
+	defer expected.Unlock()
+	expected.triggered = true
+	// converts panic to error in case of reflect value type mismatch
+	defer func(errp *error, exp *ExpectedQuery, q string, a []driver.Value) {
+		if e := recover(); e != nil {
+			if se, ok := e.(*reflect.ValueError); ok { // catch reflect error, failed type conversion
+				msg := "query \"%s\", args \"%+v\" failed to match expected arguments \"%+v\", reason %s"
+				*errp = fmt.Errorf(msg, q, a, exp.args, se)
+			} else {
+				panic(e) // overwise if unknown error panic
+			}
+		}
+	}(&err, expected, query, args)
+
+	if !expected.queryMatches(query) {
+		return nil, fmt.Errorf("query '%s', does not match regex [%s]", query, expected.sqlRegex.String())
 	}
 
-	t.triggered = true
-	if t.err != nil {
-		return nil, t.err // mocked to return error
+	if !expected.argsMatches(args) {
+		return nil, fmt.Errorf("query '%s', args %+v does not match expected %+v", query, args, expected.args)
 	}
 
-	if t.rows == nil {
-		return nil, fmt.Errorf("query '%s' with args %+v, must return a database/sql/driver.rows, but it was not set for expectation %T as %+v", query, args, t, t)
+	if expected.err != nil {
+		return nil, expected.err // mocked to return error
 	}
 
-	defer argMatcherErrorHandler(&err) // converts panic to error in case of reflect value type mismatch
-
-	if !t.queryMatches(query) {
-		return nil, fmt.Errorf("query '%s', does not match regex [%s]", query, t.sqlRegex.String())
+	if expected.rows == nil {
+		return nil, fmt.Errorf("query '%s' with args %+v, must return a database/sql/driver.rows, but it was not set for expectation %T as %+v", query, args, expected, expected)
 	}
 
-	if !t.argsMatches(args) {
-		return nil, fmt.Errorf("query '%s', args %+v does not match expected %+v", query, args, t.args)
-	}
-
-	return t.rows, err
+	return expected.rows, err
 }
 
 // ExpectQuery expects Query() or QueryRow() to be called with sql query
@@ -246,40 +342,58 @@ func (c *Sqlmock) ExpectRollback() *ExpectedRollback {
 
 // Commit meets http://golang.org/pkg/database/sql/driver/#Tx
 func (c *Sqlmock) Commit() error {
-	e := c.next()
-	if e == nil {
+	var expected *ExpectedCommit
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if expected, ok = next.(*ExpectedCommit); ok {
+			break
+		}
+
+		next.Unlock()
+		if c.MatchExpectationsInOrder {
+			return fmt.Errorf("call to commit transaction, was not expected, next expectation is %T as %+v", next, next)
+		}
+	}
+	if expected == nil {
 		return fmt.Errorf("all expectations were already fulfilled, call to commit transaction was not expected")
 	}
 
-	t, ok := e.(*ExpectedCommit)
-	if !ok {
-		return fmt.Errorf("call to commit transaction, was not expected, next expectation was %v", e)
-	}
-	t.triggered = true
-	return t.err
+	expected.triggered = true
+	expected.Unlock()
+	return expected.err
 }
 
 // Rollback meets http://golang.org/pkg/database/sql/driver/#Tx
 func (c *Sqlmock) Rollback() error {
-	e := c.next()
-	if e == nil {
+	var expected *ExpectedRollback
+	var ok bool
+	for _, next := range c.expected {
+		next.Lock()
+		if next.fulfilled() {
+			next.Unlock()
+			continue
+		}
+
+		if expected, ok = next.(*ExpectedRollback); ok {
+			break
+		}
+
+		next.Unlock()
+		if c.MatchExpectationsInOrder {
+			return fmt.Errorf("call to rollback transaction, was not expected, next expectation is %T as %+v", next, next)
+		}
+	}
+	if expected == nil {
 		return fmt.Errorf("all expectations were already fulfilled, call to rollback transaction was not expected")
 	}
 
-	t, ok := e.(*ExpectedRollback)
-	if !ok {
-		return fmt.Errorf("call to rollback transaction, was not expected, next expectation was %v", e)
-	}
-	t.triggered = true
-	return t.err
-}
-
-func argMatcherErrorHandler(errp *error) {
-	if e := recover(); e != nil {
-		if se, ok := e.(*reflect.ValueError); ok { // catch reflect error, failed type conversion
-			*errp = fmt.Errorf("Failed to compare query arguments: %s", se)
-		} else {
-			panic(e) // overwise panic
-		}
-	}
+	expected.triggered = true
+	expected.Unlock()
+	return expected.err
 }
diff --git a/sqlmock_test.go b/sqlmock_test.go
index e36a225..deb37ff 100644
--- a/sqlmock_test.go
+++ b/sqlmock_test.go
@@ -3,6 +3,7 @@ package sqlmock
 import (
 	"database/sql"
 	"fmt"
+	"sync"
 	"testing"
 	"time"
 )
@@ -575,3 +576,44 @@ func TestArgumentReflectValueTypeError(t *testing.T) {
 		t.Error("Expected error, but got none")
 	}
 }
+
+func TestGoroutineExecutionWithUnorderedExpectationMatching(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Errorf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	// note this line is important for unordered expectation matching
+	mock.MatchExpectationsInOrder = false
+
+	result := NewResult(1, 1)
+
+	mock.ExpectExec("^UPDATE one").WithArgs("one").WillReturnResult(result)
+	mock.ExpectExec("^UPDATE two").WithArgs("one", "two").WillReturnResult(result)
+	mock.ExpectExec("^UPDATE three").WithArgs("one", "two", "three").WillReturnResult(result)
+
+	var wg sync.WaitGroup
+	queries := map[string][]interface{}{
+		"one":   []interface{}{"one"},
+		"two":   []interface{}{"one", "two"},
+		"three": []interface{}{"one", "two", "three"},
+	}
+
+	wg.Add(len(queries))
+	for table, args := range queries {
+		go func(tbl string, a []interface{}) {
+			if _, err := db.Exec("UPDATE "+tbl, a...); err != nil {
+				t.Errorf("error was not expected: %s", err)
+			}
+			wg.Done()
+		}(table, args)
+	}
+
+	wg.Wait()
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expections: %s", err)
+	}
+}