Labour says it would scrap laws allowing private landlords to evict tenants without giving a reason.
The law, in force since 1988, is thought to be the biggest cause of homelessness.
Labour's shadow housing minister John Healey announced the policy at the party's conference in Liverpool.
Mr Healey also unveiled plans for a £20m fund to set up "renters' unions" to support tenants in disputes with landlords.
So-called "no-fault" evictions - when landlords throw people out of their home without saying why - have been growing in recent years.
Research by the Joseph Rowntree Foundation and the Cambridge Centre for Housing and Planning Research found 80% of private-sector evictions in 2015 fell into this category.
Before Section 21 of the 1988 Housing Act came into force it was more difficult for landlords to evict people who paid rent on time.
The government has announced plans increase security for tenants in the private rented sector, who now number about 11.5 million people, including minimum tenancies of three years.
But Labour says it would go further if it gained power.
The party's policies include:
- A new levy on second homes that are used as holiday homes
- Reversing cuts to legal aid for housing related cases
- Introducing three-year tenancies
- Banning letting agent fees
- New minimum legal standards to ensure homes are "fit for human habitation"
- Giving cities the power to introduce rent controls
In his speech to the Labour faithful in Liverpool, Mr Healey said: "Tenants who rent from private landlords have been hit hard by the housing crisis.
"Labour's commitment is clear: we'll give renters new rights to control rental costs, improve conditions and increase security.
"Renters' unions help put power in the hands of tenants.
"And the next Labour government will fund set-up costs for these unions across the country to support renters to defend their rights, and make the housing market fairer."
In response, Conservative Housing Secretary James Brokenshire said the costs of a new union for tenants would fall on "hard-pressed renters".