Dragons' Den is a British reality television business programme, presented by Evan Davis and based upon the original Japanese series. The show allows several entrepreneurs an opportunity to present their varying business ideas to a panel of five wealthy investors, the "Dragons" of the show's title, and pitch for financial investment while offering a stake of the company in return.

The first episode was broadcast on BBC Two on 4 January 2005. After 16 series on the channel, the show has been broadcast on BBC One since 2021. Reruns of previous episodes are still broadcast on BBC Two. The programme is produced by BBC Studios Factual Entertainment Productions and co-produced with Sony Pictures Television International, the owners of the format that is distributed worldwide. The show was also broadcast by UKTV channel Dave during the daytime and late nights between 2007 and 2013.

Applicants can apply to appear on the show through the BBC website; however, they may also be directly approached to appear. The final selection is based on the strength of idea, a robust business plan, and projected turnover. Selected candidates will have what they believe to be a viable and profitable business idea or already operational business, but lack start-up funding, funds for promotion or expansion. Strict rules apply that they have had no prior contact with the current panel of dragons and will sign a non-disclosure agreement, prohibiting them from publicly discussing the details of their time on the show until it has been broadcast. Between series 1 and 11, up to ten pitches were broadcast in each episode, with four individual pitches lasting around ten minutes each—a mixture of successful, rejected and failed pitches—and up to six failed pitches being shortened to a combined total of less than two minutes appearing between each. From series 12 onwards, four main pitches are broadcast lasting between ten and twenty minutes, with one or two failed pitches occasionally featured in between, lasting around three to five minutes. A BBC spokesman has stated that entrepreneurs are advised before filming that their pitch may not be broadcast for "editorial reasons", and will be informed before the series finale. Entrepreneurs' pitches selected for broadcast are contacted between a week to one month before it will be aired, allowing time for them to prepare marketing campaigns.

As part of their opening pitch, which they are advised to keep to a maximum of three to five minutes, entrepreneurs must clearly state their name, the name of the business, the amount of money they require, and the percentage of equity they would ideally give in exchange. Whilst thirty minutes is alleged to be the maximum allocated length of time per pitch, some are reported to have stretched to two hours. If the dragons believe the business plan proposed is not credible, the entrepreneurs are often subject to ridiculing on grounds that widely vary, but particularly upon knowledge of their financial forecasts/profits and overvaluation of the business. Should they cite areas of the business plan they find desirable or enticing, questioning may pause whilst the dragons think of potential routes to investment. From series 18 to series 20, following initial government guidelines on social distancing stemming from the COVID-19 pandemic, the entrepreneurs and dragons maintained a two-metre distancing, with samples of their products preplaced into a box next to each chair before the pitch started, and did not shake hands on agreeing a deal. These guidelines were discontinued from Series 21 onwards.

If the dragons see overall potential in an investment being made, the pitch will conclude with the dragons offering the full amount of money requested and negotiating the amount of equity initially offered. Offers can range from a single dragon to a unit of multiple dragons, dividing the money and equity equally. The entrepreneurs will then have the opportunity to negotiate further, accept or decline investment. Strict rules stipulate they must be offered at least the amount of money they initially requested and can only accept one respective offer. If a dragon offers less money than asked, then any remaining dragons will have to offer the remainder for the deal to be accepted. Entrepreneurs usually focus on the benefit of working with dragons who have the broadest range of expertise in their field. Negotiations vary in length of time, particularly when complex conditions are discussed. The entrepreneurs are often pressured to relinquish a larger share of equity than they had first planned, frequently leading to negotiations of 'buy-backs', reducing the dragons' equity stake once the investment is repaid or targets are met. Occasionally, the dragons offer more money than pitched for in a bid to compete for the investment, or should they believe that the entrepreneur has undervalued the business. If an offer is accepted, they leave the den with verbal assurance that they will soon be in contact. They receive the respective dragon's contact details from the producers off-screen. A dragon who does not wish to invest will declare "I'm out", and the entrepreneur should not expect any further participation from them, though on one occasion in series 4, Peter Jones continued to question an entrepreneur after stating such. Should all dragons declare themselves "out", or the entrepreneur rejects a final offer, they will leave the den with no further advice.

Filming concludes with the entrepreneurs briefly interviewed by the producers, reflecting on their pitch. Following the on-screen agreement, the pledge of investment will undergo off-screen due diligence before contracts are signed. The producers of the show do not participate in any negotiations following filming. There is no legal commitment for the dragons to fulfil their offers should the process prove unsatisfactory in any way for either party.

The opening sequence was shot in Ancoats, Manchester, an area transformed by the Industrial Revolution which helped give the city its nickname Cottonopolis. The sequence features shots of Brunswick Mill, Murrays' Mills and McConnel & Kennedy Mills, Manchester's most famous Industrial Revolution–era cotton mills, and their use maintains the programme's warehouse theme. The location at which the pitches are filmed has varied over the years. It was originally filmed inside a furniture depository in Stoke Newington. The production was forced to move after the first series owing to building work next door. For the second series shooting took place in a disused warehouse, Wool House. It was the first set created by production designer Laurence Williams, requiring the construction of a section of the window wall and the staircase down to the lower floor. The owner of this warehouse converted it into flats, necessitating a further move to Tanner Street for the next few series. Here another more extensive set was created, including cutting a hole in the floor and again creating the stairs down to the lower floor. Building work necessitated another move, this time to Pinewood Studios, only two weeks before a series was due to be shot; the production designer had to create a complete set on the film stage, including a staircase which descended down into the underfloor tank. After several more series were shot at Pinewood, the production was moved to the BBC's new home in Salford Quays at dock10, MediaCityUK. A brand-new set was created for the move and was screened in the latter part of 2012 for Series 10.

Space Studios Manchester, in Gorton, was used to film the programme from 2015 to 2017. From 2018 onward the show has been filmed at Old Granada Studios in Manchester. In October 2021, the BBC announced that it was to relocate programme production from Manchester to Glasgow.