| Honorific Prefix: | The Right Honourable Sir |
| Office: | Chief Justice of the Combined Judiciary of Sarawak, North Borneo and Brunei |
| Predecessor: | Sir Ivor Llewellyn Brace |
| Birth Date: | 16 August 1899 |
| Death Place: | Málaga, Spain |
| Resting Place: | English Cemetery, Málaga, Andalusia, Spain |
| Residence: | Caterham, Tandridge District, Surrey, England |
| Spouse: | Mary Howard Williams |
| Term Start: | 1957 |
| Term End: | 1957 |
| Citizenship: | Irish |
| Birth Place: | Cork, Munster, Ireland |
| Nominator: | Anthony Eden |
| Appointer: | Elizabeth II |
| Order: | 2nd |
| Rank: | Sergeant |
| Unit: | Hong Kong Volunteer Defence Corps |
| Allegiance: |  United Kingdom |
| Ernest Hillas Williams | |
| Office2: | Secretary for Chinese Affairs |
| Termlabel2: | Covering duties |
| Termlabel3: | Covering duties |
| Term Start3: | 5 September 1935 |
| Term End3: | 3 October 1935 |
| Battles: | World War II |
| Governor3: | Vacant |
| Monarch3: | George V |
| Monarch2: | George VI |
| 1Blankname2: | Colonial Secretary |
| 1Namedata2: | Sir Thomas Southorn |
| 1Blankname3: | Colonial Secretary |
| 1Namedata3: | Sir Thomas Southorn |
| Governor2: | Vacant |
| Term Start2: | 22 September 1937 |
| Term End2: | 20 October 1937 |
Sir Ernest Hillas Williams (16 August 1899 – 5 February 1965) was an Irish judge who served as a British Empire colonial official based for most of his career in British Hong Kong and later also the second Chief Justice of the Combined Judiciary of Sarawak, North Borneo and Brunei.
Williams received a BA in mathematics from Trinity College Dublin in 1922. While serving in the Colonial Service, Williams was promoted from colonial administrator to puisne judge and later also served as the assistant Attorney General of Hong Kong. Over the course of his time in British Hong Kong, Williams was twice appointed acting Secretary for Chinese Affairs of the Executive Council of Hong Kong.[1] Following the events of World War II, Williams was sent to British Borneo and succeeded Sir Ivor Llewellyn Brace as Chief Justice of the Combined Judiciary of Sarawak, North Borneo and Brunei.
Williams was also a sergeant in the Hong Kong Volunteer Defence Corps.[2]
Williams was a prisoner of war (POW) held at a camp in Sham Shui Po Barracks before later being moved to Innoshima, Hiroshima Prefecture by the Imperial Japanese Army.[3] [4] [5] [6]
Williams died in early February 1965 whilst in the town of Málaga, Spain.