Five referendums were held in Switzerland in 1891. 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. The second was held on 5 July on a constitutional amendment, and was approved by 60.3% of voters. 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. 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 31.1% of voters.
The two constitutional referendums were mandatory referendums, which required both a majority of voters and cantons. The other three were optional referendums, which meant that only a majority of the public vote was required for the proposals to be approved.