The Cambridge by-election of 21 September 1967 was held after the premature death of Cambridge's Labour MP (MP) Robert Davies in June 1967.
The seat was highly marginal, having only been won by Labour during the previous year's Labour landslide by 439 votes, and it had only been the second time Labour had ever taken the constituency. In the ensuing by-election, a large swing to the Conservatives saw their candidate David Lane win by 5,978 votes.