customize html normal notice when a field is required

Is it possible to modify the warning that comes by default from html ??, I'm doing a form and I need a checkbox when I put the required attribute tells me. "You must agree to terms and conditions". Is that possible?

                    <div class="form-group col-lg-12 col-xs-12 checkbox">
                        <label><input type="checkbox" name="" required>Acepto <a href="#" data-toggle="modal" data-target="#myModal">Terminos y Condiciones</a></label>
                    </div>