Wow. I took a quick look at the Wikipedia article about Stoicism and I found many similarities between it and the Dhamma.
The ancient Stoics are often misunderstood because the terms they used pertained to different concepts in the past than they do today. The word 'stoic' has come to mean 'unemotional' or indifferent to pain, because Stoic ethics taught freedom from 'passion' by following 'reason.' The Stoics did not seek to extinguish emotions, rather they sought to transform them by a resolute 'askēsis' which enables a person to develop clear judgment and inner calm. Logic, reflection, and concentration were the methods of such self-discipline.
Borrowing from the Cynics, the foundation of Stoic ethics is that good lies in the state of the soul itself; in wisdom and self-control. Stoic ethics stressed the rule: "Follow where reason leads." One must therefore strive to be free of the passions, bearing in mind that the ancient meaning of 'passion' was "anguish" or "suffering", that is, "passively" reacting to external events — somewhat different from the modern use of the word. A distinction was made between pathos (plural pathe) which is normally translated as "passion", propathos or instinctive reaction (e.g. turning pale and trembling when confronted by physical danger) and eupathos, which is the mark of the Stoic sage (sophos). The eupatheia are feelings resulting from correct judgment in the same way as the passions result from incorrect judgment.
The idea was to be free of suffering through apatheia (Greek: ἀπάθεια) or peace of mind (literally,'without passion'), where peace of mind was understood in the ancient sense — being objective or having "clear judgment" and the maintenance of equanimity in the face of life's highs and lows.
For the Stoics, 'reason' meant not only using logic, but also understanding the processes of nature — the logos, or universal reason, inherent in all things. Living according to reason and virtue, they held, is to live in harmony with the divine order of the universe, in recognition of the common reason and essential value of all people. The four cardinal virtues of the Stoic philosophy are wisdom (Sophia), courage (Andreia), justice (Dikaiosyne), and temperance (Sophrosyne), a classification derived from the teachings of Plato.
Following Socrates, the Stoics held that unhappiness and evil are the results of human ignorance of the reason in nature. If someone is unkind, it is because they are unaware of their own universal reason which would lead to the conclusion of kindness. If they are unhappy, it is because they have forgotten how nature actually functions — unhappiness is having one's unrealistic expectations of reality go unfulfilled. The solution to evil and unhappiness then, is the practice of Stoic philosophy — to examine one's own judgments and behaviour and determine where they have diverged from the universal reason of nature.