Edit in JSFiddle

$(function() {
    var This = $('.height-a'), array = [], max, h, count = This.length;
    This.each(function(i) {
        array[i] = $(this);
        h = array[i].height();
        if(i == 0 || h > max) max = h;
        if(i == count - 1) $.each(array, function() { this.height(max); });
    });
});
<div class="height-a font-1"><p>Text</p></div>
<div class="height-a font-2"><p>TextTextTextTextTextTextTextTextTextTextTextText</p></div>
<div class="height-a font-3"><p>Text</p></div>
<div class="height-a font-1"><p>TextTextTextTextTextTextTextTextText</p></div>
<div class="height-a font-2"><p>Text</p></div>
div {overflow:hidden;}
.height-a {
    background: #ededed;
    float: left;
    width: 60px;
    border: 1px solid #333;
    margin-right: 5px;
    word-break: break-all;
}
.font-1 {
    font-size: 20px;
}
.font-2 {
    font-size: 10px;
}
.font-3 {
    font-size: 30px;
}