| Alpheus Brown Alger | |
| Office: | Mayor of Cambridge, Massachusetts |
| Term Start: | January 1891 |
| Term End: | January 1892 |
| Predecessor: | Henry Gilmore |
| Successor: | William Bancroft |
| Office2: | Member of the Massachusetts State Senate Third Middlesex District |
| Term Start2: | 1886 |
| Term End2: | 1887 |
| Term Start3: | 1884 |
| Term End3: | 1884 |
| Party: | Democratic |
| Birth Date: | 8 October 1854 |
| Birth Place: | Lowell, Massachusetts |
| Alma Mater: | Harvard College, Harvard Law School |
| Occupation: | Attorney |
Alpheus Brown Alger (October 8, 1854 – May 4, 1895) was a Massachusetts politician who served in the Massachusetts State Senate, as a member of the Board of Aldermen and as the Mayor of Cambridge, Massachusetts.
Alger was born to Edwin Alden and Amanda Malvina Alger, née Buswell, in Lowell, Massachusetts.[1] From October 1875 to January 1877 Alger studied law at Harvard Law School and he was admitted to the bar for the County of Middlesex on June 4, 1877. After being admitted to the bar, he began practicing law with his father's firm, Brown & Alger in Boston while living in Cambridge. Alger was active in the Democratic party. From 1878 to 1891 Alger was a member of the Cambridge Democratic Committee, from 1884 to 1891 he was a member of Massachusetts' Democratic party state committee, and he represented Massachusetts' eight Congressional District at the 1888 Democratic National Convention. He died on May 4, 1895, in North Cambridge, Massachusetts.[2]