| 卅 |  sà | thirty |  |
| 三十 | sān shí | thirty / 30 | |
| 叁拾 | sān shí | thirty (in banker's anti-fraud numerals) | |
| 三十而立 | sān shí ér lì | thirty years old and therefore independent (idiom, from Confucius) | |
| 三七开 | sān qī kāi | ratio seventy to thirty / thirty percent failure, seventy percent success | |
| 三旬九食 | sān xún jiǔ shí | lit. to have only nine meals in thirty days (idiom) / fig. (of a family) on the brink of starvation / in dire straits | |
| 三十天 | sān shí tiān | thirty days | |
| 三十年来 | sān shí nián lái | for the past thirty years | |
| 三七开定论 | sān qī kāi dìng lùn | thirty percent failure, seventy percent success, the official PRC verdict on Mao Zedong | |
| 三十六字母 | sān shí liù zì mǔ | thirty six initial consonants of Song phonetic theory | |
| 国际经济学和货币政策协商小组 | | Consultative Group on International Economics and Monetary Policy / Group of Thirty | |
| 叁十国小组 | | Consultative Group on International Economics and Monetary Policy / Group of Thirty | |
| 三十年河东，三十年河西 | sān shí nián hé dōng , sān shí nián hé xī | the river flows thirty years to the East, thirty years to the West (proverb) / change is the only constant | |
