Company lists · Data refreshed September 2026

Top 25 Sales call center outsourcing companies worldwide

Name: Sales call center outsourcing companies worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 29, 2026 11,142 companies tracked

RevenueBase identified 11,142 sales call center outsourcing companies worldwide as of September 2026 and tracks 293,619 professional contacts across them, including 21,910 with verified work emails. The United States is the largest market and London the largest hub.

This list covers sales call center outsourcing companies worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 29, 2026. Country and city lists for sales call center outsourcing companies follow the table.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 29, 2026 86% judged on-target in blind review

11,142Companies

293,619Contacts tracked

21,910Verified emails

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The 25 largest sales call center outsourcing companies worldwide

Ranked by team size

Top 25 of 11,142 sales call center outsourcing companies worldwide, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to sales call center outsourcing companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	IBEX	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	10001+	15,457 contacts →
	Partial evidence “ibex delivers innovative business process outsourcing (BPO), smart digital marketing, online acquisition technology, and end-to-end customer engagement solutions to help companies…” Source: RevenueBase Database · checked Sep 29, 2026
2	Afni, INC	Partial evidence	Bloomington, IL, United StatesHQ checked Sep 29, 2026	10001+	5,553 contacts →
	Partial evidence “When people reach for their phones, use laptops, or grab their tablets, Afni's contact center teams are there to provide prompt and friendly help.” Source: RevenueBase Database · checked Sep 29, 2026
3	Emtelco S.A	Indirect evidence	Medellín, ColombiaHQ checked Sep 29, 2026	10001+	4,998 contacts →
	Indirect evidence “Maximizamos el valor de cada contacto de las empresas con sus clientes, gestionando los procesos de relacionamiento a través de canales tefónicos, virtuales y presenciales.” Source: RevenueBase Database · checked Sep 29, 2026
4	Ibex. Pakistan	Indirect evidence	Karachi, PakistanHQ checked Sep 29, 2026	10001+	4,161 contacts →
	Indirect evidence “ibex.” Source: RevenueBase Database · checked Sep 29, 2026
5	Callink	Strong evidence	Uberlândia, BrazilHQ checked Sep 29, 2026	5,001-10,000	4,126 contacts →
	Strong evidence “Mais que call center: soluções que transformam o seu negócio e a jornada dos clientes!” Source: RevenueBase Database · checked Sep 29, 2026
6	Sercom	Partial evidence	Taboão Da Serra, BrazilHQ checked Sep 29, 2026	5,001-10,000	3,785 contacts →
	Partial evidence “Founded in 1993, since the beginning Sercom has stood out in the Contact Center Services.” Source: RevenueBase Database · checked Sep 29, 2026
7	GSS Global Sales Solutions	Indirect evidence	Madrid, SpainHQ checked Sep 29, 2026	10001+	3,716 contacts →
	Indirect evidence “is a tech company specialized in providing, and for.” Source: RevenueBase Database · checked Sep 29, 2026
8	Telvista	Indirect evidence	Dallas, TX, United StatesHQ checked Sep 29, 2026	1,001-5,000	3,122 contacts →
	Indirect evidence “Email: info@Telvista.com Telvista is a premier provider of contact solutions that drive customer loyalty and create competitive advantage for our clients.” Source: RevenueBase Database · checked Sep 29, 2026
9	Advanced Call Center Technologies, LLC	Strong evidence	Berwyn, PA, United StatesHQ checked Sep 29, 2026	5,001-10,000	2,774 contacts →
	Strong evidence “Advanced Call Center Technologies, LLC (ACT) is a premier provider of domestic (USA), near shore and far shore outsourced call center services to the financial services, mortgage…” Source: RevenueBase Database · checked Sep 29, 2026
10	CAT Technologies Argentina	Strong evidence	Buenos Aires, ArgentinaHQ checked Sep 29, 2026	1,001-5,000	2,221 contacts →
	Strong evidence “Somos la compañía líder en Servicios Next Gen de Contact Center, Business Process Outsourcing (BPO) y Customer Experience (CX).” Source: RevenueBase Database · checked Sep 29, 2026
11	Transcosmos INC	Indirect evidence	Toshima-ku, JapanHQ checked Sep 29, 2026	10001+	1,987 contacts →
	Indirect evidence “transcosmos launched its operations in 1966.” Source: RevenueBase Database · checked Sep 29, 2026
12	Infocision Management Corporation	Partial evidence	Akron, OH, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,764 contacts →
	Partial evidence “InfoCision is an award-winning contact center partner trusted by leading brands for over 40 years.” Source: RevenueBase Database · checked Sep 29, 2026
13	Km2 Solutions	Partial evidence	Boca Raton, FL, United StatesHQ checked Sep 29, 2026	5,001-10,000	1,741 contacts →
	Partial evidence “Award-winning outsourcing partner with two decades of experience operating an exclusively nearshore strategy that delivers better performance, close to home, and at a lower cost.” Source: RevenueBase Database · checked Sep 29, 2026
14	Supportninja	Indirect evidence	Austin, TX, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,711 contacts →
	Indirect evidence “SupportNinja provides customer experience and back-office support services for tech companies and startups around the world.” Source: RevenueBase Database · checked Sep 29, 2026
15	Support Services Group	Partial evidence	Waco, TX, United StatesHQ checked Sep 29, 2026	5,001-10,000	1,710 contacts →
	Partial evidence “Support Services Group (SSG) helps businesses accelerate growth and earn customers for life through high-touch, outsourced engagement center services.” Source: RevenueBase Database · checked Sep 29, 2026
16	Dialamerica	Indirect evidence	Mahwah, NJ, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,536 contacts →
	Indirect evidence “DialAmerica is now Aucera.” Source: RevenueBase Database · checked Sep 29, 2026
17	RDI Corporation	Indirect evidence	Cincinnati, OH, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,484 contacts →
	Indirect evidence “At RDI, we believe in winning smart by providing customized, strategic solutions to our clients.” Source: RevenueBase Database · checked Sep 29, 2026
18	Outworx Contact Centre	Indirect evidence	Durban, South AfricaHQ checked Sep 29, 2026	1,001-5,000	1,453 contacts →
	Indirect evidence “One voice – let us be your voice.” Source: RevenueBase Database · checked Sep 29, 2026
19	Datamark, INC	Strong evidence	El Paso, TX, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,418 contacts →
	Strong evidence “DATAMARK Inc, a provider of omni-channel contact centers and business process outsourcing (BPO) services since 1989, employs more than at our facilities in the United States…” Source: RevenueBase Database · checked Sep 29, 2026
20	Full Potential Solutions	Partial evidence	Waltham, MA, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,238 contacts →
	Partial evidence “Full Potential Solutions (FPS) is a new kind of performance-based outsourcing firm that puts culture and employees first, because we believe that happy, fulfilled teams accomplish…” Source: RevenueBase Database · checked Sep 29, 2026
21	American Call Center	Partial evidence	Guayaquil, EcuadorHQ checked Sep 29, 2026	1,001-5,000	1,225 contacts →
	Partial evidence “We deliver tailored Contact Center and Back Office solutions to our strategic partners, leveraging advanced technology and high quality standards to elevate customer experiences…” Source: RevenueBase Database · checked Sep 29, 2026
22	The Office Gurus	Strong evidence	St Petersburg, FL, RussiaHQ checked Sep 29, 2026	1,001-5,000	1,198 contacts →
	Strong evidence “The Office Gurus (TOG) is a global call center and business process outsource provider of customer care, telemarketing, lead generation, appointment setting, order entry, accounts…” Source: RevenueBase Database · checked Sep 29, 2026
23	crystel.co	Partial evidence	Amman, JordanHQ checked Sep 29, 2026	1,001-5,000	1,128 contacts →
	Partial evidence “Crystel emerged as a leading Outsourcing Service Provider (OSP) since its establishment in Jordan in early 2007.” Source: RevenueBase Database · checked Sep 29, 2026
24	Ventas Y Servicios S.A	Strong evidence	Bogotá D.c., ColombiaHQ checked Sep 29, 2026	1,001-5,000	1,116 contacts →
	Strong evidence “MISIÓN Somos una compañía de Contact Center y tercerización de procesos (Business Process Outsourcing BPO), rentable, con presencia nacional; que brinda soluciones ágiles y…” Source: RevenueBase Database · checked Sep 29, 2026
25	Evoltis	Partial evidence	Córdoba, ArgentinaHQ checked Sep 29, 2026	1,001-5,000	1,092 contacts →
	Partial evidence “At Evoltis, we collaborate to improve every interaction with your customers, driving Innovation through our Contact Center & BPO and Technology Development services to achieve a…” Source: RevenueBase Database · checked Sep 29, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: sales call center outsourcing companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names sales call center outsourcing companies.
Partial evidence: Its own public description names part of sales call center outsourcing companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name sales call center outsourcing companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 11,142 sales call center outsourcing companies worldwide

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Sales call center outsourcing companies worldwide at a glance

As of Sep 29, 2026

7.5%Verified-email coverage

26.4Average contacts per company

11-50Median size (employees)

1.5%Largest-city concentration · London

Sep 29, 2026Page data refreshed

Companies by employee count

1-10

3,420

11-50

3,903

51-200

2,368

201-500

779

501-1,000

332

1,001-5,000

246

5,001-10,000

10001+

Email recency is reported on each country list linked below.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among sales call center outsourcing companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
Coverage: Every country. Country and city lists for sales call center outsourcing companies are linked below.
What qualifies: Companies worldwide whose own description of what they do matches “sales call center outsourcing companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names sales call center outsourcing companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among sales call center outsourcing companies, and records with no verified work email.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 21,910 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 29, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Sales call center outsourcing companies by location

58 lists · largest first

Every Sales call center outsourcing companies list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names sales call center outsourcing companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many sales call center outsourcing companies are there worldwide?

RevenueBase identified 11,142 sales call center outsourcing companies worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

IBEX, headquartered in Washington, tops this list with the largest team on record.

Which country has the most sales call center outsourcing companies?

The United States leads with 2,023 companies, followed by India (998) and Pakistan (690). Every sales call center outsourcing companies list by country and city is linked on this page.

Which city has the most sales call center outsourcing companies?

London leads with 172 headquartered companies, followed by Lahore (167) and Rawalpindi (152).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 21,910 verified decision-maker contacts tracked across these 11,142 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 29, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.