Five referendums were held in Switzerland in 1891.^[1] The first was held on 15 March on a federal law on federal officials who had become unemployable due to disability, and was rejected by 79.4% of voters.^[1] The second was held on 5 July on a constitutional amendment, and was approved by 60.3% of voters.^[1] Two referendums were held on 18 October, one on revising article 39 of the federal constitution and one on a federal law on Swiss tariffs; both were approved.^[1] The last was held on 6 December on the question of whether the federal government should purchase the Swiss Central Railway, but was rejected by 68.9% of voters.^[1]

The two constitutional referendums were mandatory referendums,^[1] which required both a majority of voters and cantons.^[2] The other three were optional referendums,^[1] which meant that only a majority of the public vote was required for the proposals to be approved.^[2]